プログラミング初心者です。  
ruby 2.5.7  
Rails 5.2.0

railsチュートリアルの１章、{1.5.3}を行っています。  
vagrant環境内でただ文字が表示されるだけの「hello_app」というアプリを作り、デプロイをしようとしており、

```

    $ git push heroku master
    
```

まではうまくいったのですが、ブラウザ表示ができません。

`heroku open` コマンドでは以下の様になり、

```

     $ heroku open
         ▸    Error opening web browser.
         ▸    Error: Exited with code 3
         ▸    
         ▸    Manually visit https://boiling-inlet-44956.herokuapp.com/ in your browser.
    
```

ブラウザでURLを直接指定するとブラウザに以下の様に表示されます。

```

    Application error
    An error occurred in the application and your page could not be served. If you are the application owner, check your logs for details. You can do this from the Heroku CLI with the command
    heroku logs --tail
    
```

`heroku logs --tail`コマンドを行うと長いですが以下の様になります。

```

    vagrant@ubuntu-bionic:/vagrant/hello_app$ heroku logs --tail
    2019-12-13T11:05:17.328479+00:00 app[web.1]: /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:11:in `require': libruby.so.2.5: cannot open shared object file: No such file or directory - /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack/msgpack.so (LoadError)
    2019-12-13T11:05:17.328499+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:11:in `rescue in <top (required)>'
    2019-12-13T11:05:17.328502+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:8:in `<top (required)>'
    2019-12-13T11:05:17.328505+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `require'
    2019-12-13T11:05:17.328525+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `block in <top (required)>'
    2019-12-13T11:05:17.328527+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/explicit_require.rb:43:in `rescue in with_gems'
    2019-12-13T11:05:17.328529+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/explicit_require.rb:39:in `with_gems'
    2019-12-13T11:05:17.328533+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `<top (required)>'
    2019-12-13T11:05:17.328534+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache.rb:74:in `require_relative'
    2019-12-13T11:05:17.328536+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache.rb:74:in `<top (required)>'
    2019-12-13T11:05:17.328539+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap.rb:3:in `require_relative'
    2019-12-13T11:05:17.328541+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap.rb:3:in `<top (required)>'
    2019-12-13T11:05:17.328544+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/setup.rb:1:in `require_relative'
    2019-12-13T11:05:17.328547+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/setup.rb:1:in `<top (required)>'
    2019-12-13T11:05:17.328550+00:00 app[web.1]: from /app/config/boot.rb:4:in `require'
    2019-12-13T11:05:17.328569+00:00 app[web.1]: from /app/config/boot.rb:4:in `<top (required)>'
    2019-12-13T11:05:17.328571+00:00 app[web.1]: from bin/rails:8:in `require_relative'
    2019-12-13T11:05:17.328576+00:00 app[web.1]: from bin/rails:8:in `<main>'
    2019-12-13T11:06:15.941821+00:00 app[api]: Starting process with command `set -e
    2019-12-13T11:06:15.941821+00:00 app[api]: mkdir -p tmp/repo_tmp/unpack
    2019-12-13T11:06:15.941821+00:00 app[api]: cd tmp/repo_tmp
    2019-12-13T11:06:15.941821+00:00 app[api]: curl -fo repo-cache.tgz 'https://s3-external-1.amazonaws.com/heroku_repos/heroku.com/cache/155667281.tgz?AWSAccessKeyId=AKIAIO4SD3DCRO7W6IJQ&Signature=YhboIS1zj4Exk91eTmeQSUJe8OM%3D&Expires=1576238773'
    2019-12-13T11:06:15.941821+00:00 app[api]: cd unpack
    2019-12-13T11:06:15.941821+00:00 app[api]: tar -zxf ../repo-cache.tgz
    2019-12-13T11:06:15.941821+00:00 app[api]: METADATA="vendor/heroku"
    2019-12-13T11:06:15.941821+00:00 app[api]: if [ -d "$METADATA" ]; then
    2019-12-13T11:06:15.941821+00:00 app[api]: TMPDIR=`mktemp -d`
    2019-12-13T11:06:15.941821+00:00 app[api]: cp -rf $METADATA $TMPDIR
    2019-12-13T11:06:15.941821+00:00 app[api]: fi
    2019-12-13T11:06:15.941821+00:00 app[api]: cd ..
    2019-12-13T11:06:15.941821+00:00 app[api]: rm -rf unpack
    2019-12-13T11:06:15.941821+00:00 app[api]: mkdir unpack
    2019-12-13T11:06:15.941821+00:00 app[api]: cd unpack
    2019-12-13T11:06:15.941821+00:00 app[api]: TMPDATA="$TMPDIR/heroku"
    2019-12-13T11:06:15.941821+00:00 app[api]: VENDOR="vendor"
    2019-12-13T11:06:15.941821+00:00 app[api]: if [ -d "$TMPDATA" ]; then
    2019-12-13T11:06:15.941821+00:00 app[api]: mkdir $VENDOR
    2019-12-13T11:06:15.941821+00:00 app[api]: cp -rf $TMPDATA $VENDOR
    2019-12-13T11:06:15.941821+00:00 app[api]: rm -rf $TMPDIR
    2019-12-13T11:06:15.941821+00:00 app[api]: fi
    2019-12-13T11:06:15.941821+00:00 app[api]: tar -zcf ../cache-repack.tgz .
    2019-12-13T11:06:15.941821+00:00 app[api]: curl -fo /dev/null --upload-file ../cache-repack.tgz 'https://s3-external-1.amazonaws.com/heroku_repos/heroku.com/cache/155667281.tgz?AWSAccessKeyId=AKIAIO4SD3DCRO7W6IJQ&Signature=9PqFzVwldNhNR65GctzeV5GKi9E%3D&Expires=1576238774'
    2019-12-13T11:06:15.941821+00:00 app[api]: exit` by user ******@gmail.com
    2019-12-13T11:06:19.498994+00:00 heroku[run.4115]: State changed from starting to up
    2019-12-13T11:06:19.674136+00:00 heroku[run.4115]: Awaiting client
    2019-12-13T11:06:19.715556+00:00 heroku[run.4115]: Starting process with command `set -e mkdir -p tmp/repo_tmp/unpack cd tmp/repo_tmp curl -fo repo-cache.tgz 'https://s3-external-1.amazonaws.com/heroku_repos/heroku.com/cache/155667281.tgz?AWSAccessKeyId=AKIAIO4SD3DCRO7W6IJQ&Signature=YhboIS1zj4Exk91eTmeQSUJe8OM%3D&Expires=1576238773' cd unpack tar -zxf ../repo-cache.tgz METADATA="vendor/heroku" if [ -d "$METADATA" ]; then   TMPDIR=`mktemp -d`   cp -rf $METADATA $TMPDIR fi cd .. rm -rf unpack mkdir unpack cd unpack TMPDATA="$TMPDIR/heroku" VENDOR="vendor" if [ -d "$TMPDATA" ]; then   mkdir $VENDOR   cp -rf $TMPDATA $VENDOR   rm -rf $TMPDIR fi tar -zcf ../cache-repack.tgz . curl -fo /dev/null --upload-file ../cache-repack.tgz 'https://s3-external-1.amazonaws.com/heroku_repos/heroku.com/cache/155667281.tgz?AWSAccessKeyId=AKIAIO4SD3DCRO7W6IJQ&Signature=9PqFzVwldNhNR65GctzeV5GKi9E%3D&Expires=1576238774' exit`
    2019-12-13T11:06:25.988415+00:00 heroku[run.4115]: State changed from up to complete
    2019-12-13T11:06:25.967422+00:00 heroku[run.4115]: Process exited with status 0
    2019-12-13T11:07:50.000000+00:00 app[api]: Build started by user ******@gmail.com
    2019-12-13T11:08:57.714711+00:00 heroku[web.1]: State changed from crashed to starting
    2019-12-13T11:08:57.380987+00:00 app[api]: Release v7 created by user ******@gmail.com
    2019-12-13T11:08:57.380987+00:00 app[api]: Deploy f4b55637 by user ******@gmail.com
    2019-12-13T11:09:00.107816+00:00 heroku[web.1]: Starting process with command `bin/rails server -p 8443 -e production`
    2019-12-13T11:09:00.000000+00:00 app[api]: Build succeeded
    2019-12-13T11:09:02.462006+00:00 heroku[web.1]: State changed from starting to crashed
    2019-12-13T11:09:02.378932+00:00 app[web.1]: /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:11:in `require': libruby.so.2.5: cannot open shared object file: No such file or directory - /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack/msgpack.so (LoadError)
    2019-12-13T11:09:02.378982+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:11:in `rescue in <top (required)>'
    2019-12-13T11:09:02.378988+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:8:in `<top (required)>'
    2019-12-13T11:09:02.378990+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `require'
    2019-12-13T11:09:02.378992+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `block in <top (required)>'
    2019-12-13T11:09:02.378994+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/explicit_require.rb:43:in `rescue in with_gems'
    2019-12-13T11:09:02.378998+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/explicit_require.rb:39:in `with_gems'
    2019-12-13T11:09:02.379000+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `<top (required)>'
    2019-12-13T11:09:02.379002+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache.rb:74:in `require_relative'
    2019-12-13T11:09:02.379003+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache.rb:74:in `<top (required)>'
    2019-12-13T11:09:02.379051+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap.rb:3:in `require_relative'
    2019-12-13T11:09:02.379053+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap.rb:3:in `<top (required)>'
    2019-12-13T11:09:02.379056+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/setup.rb:1:in `require_relative'
    2019-12-13T11:09:02.379058+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/setup.rb:1:in `<top (required)>'
    2019-12-13T11:09:02.379061+00:00 app[web.1]: from /app/config/boot.rb:4:in `require'
    2019-12-13T11:09:02.379063+00:00 app[web.1]: from /app/config/boot.rb:4:in `<top (required)>'
    2019-12-13T11:09:02.379065+00:00 app[web.1]: from bin/rails:8:in `require_relative'
    2019-12-13T11:09:02.379069+00:00 app[web.1]: from bin/rails:8:in `<main>'
    2019-12-13T11:09:02.439865+00:00 heroku[web.1]: Process exited with status 1
    2019-12-13T11:09:43.027954+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=boiling-inlet-44956.herokuapp.com request_id=77687982-8e4d-4278-b965-65e7109264d3 fwd="220.144.186.147" dyno= connect= service= status=503 bytes= protocol=https
    2019-12-13T11:09:43.797322+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=boiling-inlet-44956.herokuapp.com request_id=c50b5f88-c956-4d3e-9ad9-a42147866545 fwd="220.144.186.147" dyno= connect= service= status=503 bytes= protocol=https
    2019-12-13T11:17:11.655899+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=boiling-inlet-44956.herokuapp.com request_id=15164495-1883-4c61-bea2-90d60b510b20 fwd="220.144.186.147" dyno= connect= service= status=503 bytes= protocol=https
    2019-12-13T11:17:12.484512+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=boiling-inlet-44956.herokuapp.com request_id=035231b6-2db3-4322-b793-fa46f6eba0a2 fwd="220.144.186.147" dyno= connect= service= status=503 bytes= protocol=https
    2019-12-13T11:26:38.605356+00:00 heroku[web.1]: State changed from crashed to starting
    2019-12-13T11:26:42.068480+00:00 heroku[web.1]: Starting process with command `bin/rails server -p 27644 -e production`
    2019-12-13T11:26:44.219808+00:00 heroku[web.1]: State changed from starting to crashed
    2019-12-13T11:26:44.160600+00:00 app[web.1]: /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:11:in `require': libruby.so.2.5: cannot open shared object file: No such file or directory - /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack/msgpack.so (LoadError)
    2019-12-13T11:26:44.160650+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:11:in `rescue in <top (required)>'
    2019-12-13T11:26:44.160686+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:8:in `<top (required)>'
    2019-12-13T11:26:44.160730+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `require'
    2019-12-13T11:26:44.160737+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `block in <top (required)>'
    2019-12-13T11:26:44.160742+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/explicit_require.rb:43:in `rescue in with_gems'
    2019-12-13T11:26:44.160744+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/explicit_require.rb:39:in `with_gems'
    2019-12-13T11:26:44.160746+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `<top (required)>'
    2019-12-13T11:26:44.160747+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache.rb:74:in `require_relative'
    2019-12-13T11:26:44.160749+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache.rb:74:in `<top (required)>'
    2019-12-13T11:26:44.160750+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap.rb:3:in `require_relative'
    2019-12-13T11:26:44.160754+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap.rb:3:in `<top (required)>'
    2019-12-13T11:26:44.160755+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/setup.rb:1:in `require_relative'
    2019-12-13T11:26:44.160757+00:00 app[web.1]: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/setup.rb:1:in `<top (required)>'
    2019-12-13T11:26:44.160765+00:00 app[web.1]: from /app/config/boot.rb:4:in `require'
    2019-12-13T11:26:44.160770+00:00 app[web.1]: from /app/config/boot.rb:4:in `<top (required)>'
    2019-12-13T11:26:44.160772+00:00 app[web.1]: from bin/rails:8:in `require_relative'
    2019-12-13T11:26:44.160774+00:00 app[web.1]: from bin/rails:8:in `<main>'
    2019-12-13T11:26:44.200208+00:00 heroku[web.1]: Process exited with status 1
    
```

`$ heroku run rails console` すると以下の様になります。

```

    $ heroku run rails console
    Running rails console on ⬢ boiling-inlet-44956... up, run.9914 (Free)
    Traceback (most recent call last):
        17: from /app/bin/rails:8:in `<main>'
        16: from /app/bin/rails:8:in `require_relative'
        15: from /app/config/boot.rb:4:in `<top (required)>'
        14: from /app/config/boot.rb:4:in `require'
        13: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/setup.rb:1:in `<top (required)>'
        12: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/setup.rb:1:in `require_relative'
        11: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap.rb:3:in `<top (required)>'
        10: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap.rb:3:in `require_relative'
         9: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache.rb:74:in `<top (required)>'
         8: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache.rb:74:in `require_relative'
         7: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `<top (required)>'
         6: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/explicit_require.rb:39:in `with_gems'
         5: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/explicit_require.rb:43:in `rescue in with_gems'
         4: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `block in <top (required)>'
         3: from /app/vendor/bundle/ruby/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/store.rb:3:in `require'
         2: from /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:8:in `<top (required)>'
         1: from /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:11:in `rescue in <top (required)>'
    /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack.rb:11:in `require': libruby.so.2.5: cannot open shared object file: No such file or directory - /app/vendor/bundle/ruby/2.5.0/gems/msgpack-1.3.1/lib/msgpack/msgpack.so (LoadError)
    
```

解決方法を色々探していて、下記のサイトを参考に、heroku側のキャッシュの削除を行いました。  
<https://teratail.com/questions/96685>

```

    $ heroku plugins:install heroku-repo
    $ heroku repo:purge_cache
    
```

その後再びherokuへコミットを行いましたが、解決しませんでした。

理解が足りていない為的外れかもしれませんが、下記の様なことも関係しているのか？と考えています。

  * railsチュートリアル上ではクラウドIDEを使うのを推奨しているが、自分の場合はvagrantを使って別のrailsアプリを作っていたりするので、vagrantで rails new するところから始めている 
  * チュートリアルではgemのバージョンを指定しているが、rails serverが起動しないerrorを回避する為にチュートリアル通りのバージョンにしていない

似た様な質問をされている方々も貼っていることが多い様でしたので、  
GemfileとGemfile.lockもコピペします。

Gemfile

```

    source 'https://rubygems.org'
    
    gem 'rails',        '5.2'
    gem 'puma',         '3.9.1'
    gem 'sass-rails',   '5.0.6'
    gem 'uglifier',     '3.2.0'
    gem 'coffee-rails', '4.2.2'
    gem 'jquery-rails', '4.3.1'
    gem 'turbolinks',   '5.0.1'
    gem 'jbuilder',     '2.6.4'
    gem 'bootsnap', require: false
    
    group :development, :test do
      gem 'sqlite3',      '1.3.13'
      gem 'byebug', '9.0.6', platform: :mri
    end
    
    group :development do
      gem 'web-console',           '3.5.1'
      gem 'listen',                '3.1.5'
      gem 'spring',                '2.0.2'
      gem 'spring-watcher-listen', '2.0.1'
    end
    
    group :production do
      gem 'pg', '0.20.0'
    end
    
```

Gemfile.lock

```

    GEM
      remote: https://rubygems.org/
      specs:
        actioncable (5.2.0)
          actionpack (= 5.2.0)
          nio4r (~> 2.0)
          websocket-driver (>= 0.6.1)
        actionmailer (5.2.0)
          actionpack (= 5.2.0)
          actionview (= 5.2.0)
          activejob (= 5.2.0)
          mail (~> 2.5, >= 2.5.4)
          rails-dom-testing (~> 2.0)
        actionpack (5.2.0)
          actionview (= 5.2.0)
          activesupport (= 5.2.0)
          rack (~> 2.0)
          rack-test (>= 0.6.3)
          rails-dom-testing (~> 2.0)
          rails-html-sanitizer (~> 1.0, >= 1.0.2)
        actionview (5.2.0)
          activesupport (= 5.2.0)
          builder (~> 3.1)
          erubi (~> 1.4)
          rails-dom-testing (~> 2.0)
          rails-html-sanitizer (~> 1.0, >= 1.0.3)
        activejob (5.2.0)
          activesupport (= 5.2.0)
          globalid (>= 0.3.6)
        activemodel (5.2.0)
          activesupport (= 5.2.0)
        activerecord (5.2.0)
          activemodel (= 5.2.0)
          activesupport (= 5.2.0)
          arel (>= 9.0)
        activestorage (5.2.0)
          actionpack (= 5.2.0)
          activerecord (= 5.2.0)
          marcel (~> 0.3.1)
        activesupport (5.2.0)
          concurrent-ruby (~> 1.0, >= 1.0.2)
          i18n (>= 0.7, < 2)
          minitest (~> 5.1)
          tzinfo (~> 1.1)
        arel (9.0.0)
        bindex (0.8.1)
        bootsnap (1.4.5)
          msgpack (~> 1.0)
        builder (3.2.4)
        byebug (9.0.6)
        coffee-rails (4.2.2)
          coffee-script (>= 2.2.0)
          railties (>= 4.0.0)
        coffee-script (2.4.1)
          coffee-script-source
          execjs
        coffee-script-source (1.12.2)
        concurrent-ruby (1.1.5)
        crass (1.0.5)
        erubi (1.9.0)
        execjs (2.7.0)
        ffi (1.11.3)
        globalid (0.4.2)
          activesupport (>= 4.2.0)
        i18n (1.7.0)
          concurrent-ruby (~> 1.0)
        jbuilder (2.6.4)
          activesupport (>= 3.0.0)
          multi_json (>= 1.2)
        jquery-rails (4.3.1)
          rails-dom-testing (>= 1, < 3)
          railties (>= 4.2.0)
          thor (>= 0.14, < 2.0)
        listen (3.1.5)
          rb-fsevent (~> 0.9, >= 0.9.4)
          rb-inotify (~> 0.9, >= 0.9.7)
          ruby_dep (~> 1.2)
        loofah (2.4.0)
          crass (~> 1.0.2)
          nokogiri (>= 1.5.9)
        mail (2.7.1)
          mini_mime (>= 0.1.1)
        marcel (0.3.3)
          mimemagic (~> 0.3.2)
        method_source (0.9.2)
        mimemagic (0.3.3)
        mini_mime (1.0.2)
        mini_portile2 (2.4.0)
        minitest (5.13.0)
        msgpack (1.3.1)
        multi_json (1.14.1)
        nio4r (2.5.2)
        nokogiri (1.10.7)
          mini_portile2 (~> 2.4.0)
        pg (0.20.0)
        puma (3.9.1)
        rack (2.0.7)
        rack-test (1.1.0)
          rack (>= 1.0, < 3)
        rails (5.2.0)
          actioncable (= 5.2.0)
          actionmailer (= 5.2.0)
          actionpack (= 5.2.0)
          actionview (= 5.2.0)
          activejob (= 5.2.0)
          activemodel (= 5.2.0)
          activerecord (= 5.2.0)
          activestorage (= 5.2.0)
          activesupport (= 5.2.0)
          bundler (>= 1.3.0)
          railties (= 5.2.0)
          sprockets-rails (>= 2.0.0)
        rails-dom-testing (2.0.3)
          activesupport (>= 4.2.0)
          nokogiri (>= 1.6)
        rails-html-sanitizer (1.3.0)
          loofah (~> 2.3)
        railties (5.2.0)
          actionpack (= 5.2.0)
          activesupport (= 5.2.0)
          method_source
          rake (>= 0.8.7)
          thor (>= 0.18.1, < 2.0)
        rake (13.0.1)
        rb-fsevent (0.10.3)
        rb-inotify (0.10.0)
          ffi (~> 1.0)
        ruby_dep (1.5.0)
        sass (3.7.4)
          sass-listen (~> 4.0.0)
        sass-listen (4.0.0)
          rb-fsevent (~> 0.9, >= 0.9.4)
          rb-inotify (~> 0.9, >= 0.9.7)
        sass-rails (5.0.6)
          railties (>= 4.0.0, < 6)
          sass (~> 3.1)
          sprockets (>= 2.8, < 4.0)
          sprockets-rails (>= 2.0, < 4.0)
          tilt (>= 1.1, < 3)
        spring (2.0.2)
          activesupport (>= 4.2)
        spring-watcher-listen (2.0.1)
          listen (>= 2.7, < 4.0)
          spring (>= 1.2, < 3.0)
        sprockets (3.7.2)
          concurrent-ruby (~> 1.0)
          rack (> 1, < 3)
        sprockets-rails (3.2.1)
          actionpack (>= 4.0)
          activesupport (>= 4.0)
          sprockets (>= 3.0.0)
        sqlite3 (1.3.13)
        thor (0.20.3)
        thread_safe (0.3.6)
        tilt (2.0.10)
        turbolinks (5.0.1)
          turbolinks-source (~> 5)
        turbolinks-source (5.2.0)
        tzinfo (1.2.5)
          thread_safe (~> 0.1)
        uglifier (3.2.0)
          execjs (>= 0.3.0, < 3)
        web-console (3.5.1)
          actionview (>= 5.0)
          activemodel (>= 5.0)
          bindex (>= 0.4.0)
          railties (>= 5.0)
        websocket-driver (0.7.1)
          websocket-extensions (>= 0.1.0)
        websocket-extensions (0.1.4)
    
    PLATFORMS
      ruby
    
    DEPENDENCIES
      bootsnap
      byebug (= 9.0.6)
      coffee-rails (= 4.2.2)
      jbuilder (= 2.6.4)
      jquery-rails (= 4.3.1)
      listen (= 3.1.5)
      pg (= 0.20.0)
      puma (= 3.9.1)
      rails (= 5.2)
      sass-rails (= 5.0.6)
      spring (= 2.0.2)
      spring-watcher-listen (= 2.0.1)
      sqlite3 (= 1.3.13)
      turbolinks (= 5.0.1)
      uglifier (= 3.2.0)
      web-console (= 3.5.1)
    
    BUNDLED WITH
       2.0.2
    
```

どなたか分かる方、教えてください。よろしくお願いいたします。
CC BY-SA 4.0
2019-12-13T12:20:56.920
61416
2022-07-28T16:05:00.497
2019-12-13T12:37:02.487
32986
37060
question
ruby-on-rails heroku デプロイ
Herokuへデプロイしたアプリのブラウザ表示で「Application error」となる
以下のページを参考にしたところ（というか書いてある通りに行ったところ）、解決しました！

[【初心者向け】railsアプリをherokuを使って確実にデプロイする方法【決定版】](https://qiita.com/kazukimatsumoto/items/a0daa7281a3948701c39)

結局何が原因だったのかはわかりませんが、Gemfileの設定、config/datebase.ymlの設定、config/environments/production.rbの設定、bin以下のフォルダの設定をした後に、  
Railsアプリとherokuの紐づけをしてデプロイしたところうまくいきました。
CC BY-SA 4.0
2019-12-17T10:44:59.250
61515
2021-12-02T02:05:20.907
2021-12-02T02:05:20.907
3060
37060
61416
answer