I can't get the pg gem to install.  I have tried --with-pg_config and it didn't work.Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension./usr/local/rvm/rubies/ruby-1.9.3-p194/bin/ruby extconf.rb checking for pg_config... noNo pg_config... trying anyway. If building fails, please try again with --with-pg-config=/path/to/pg_configchecking for libpq-fe.h... noCan't find the 'libpq-fe.h header*** extconf.rb failed ***Could not create Makefile due to some reason, probably lack ofnecessary libraries and/or headers.  Check the mkmf.log file for moredetails.  You may need configuration options.
Can't install pg gem
ubuntu;compiling;software installation;ruby
Can't find the 'libpq-fe.h headerIf you haven't done it already, install and initialize apt-file. This tool tells you what package contains a file with the given name.sudo apt-get install apt-fileapt-file updateThen run apt-file search libpq-fe.h to find out what package contains this file, and install the package in question. (It's libpq-dev.)You can also search for this file name in some package installation GUIs, or online.