Migration warns for phantom part changes 
Here is the warning:

```
Your models in app(s): 'part' have changes that are not yet reflected in a migration, and so won't be applied.
Run 'manage.py makemigrations' to make new migrations, and then re-run 'manage.py migrate' to apply them.
```

Running `manage.py makemigrations` does **not** generate new migration file...

Running `manage.py showmigrations part` shows all part migrations are complete.

I found this warning both with PostGreSQL and SQLite3, if that has anything to do with backend dependency.
diff --git a/InvenTree/InvenTree/fields.py b/InvenTree/InvenTree/fields.py
index 462d2b0e0..cd98bf50c 100644
--- a/InvenTree/InvenTree/fields.py
+++ b/InvenTree/InvenTree/fields.py
@@ -55,7 +55,7 @@ class InvenTreeModelMoneyField(ModelMoneyField):
     
     def __init__(self, **kwargs):
         # detect if creating migration
-        if 'makemigrations' in sys.argv:
+        if 'migrate' in sys.argv or 'makemigrations' in sys.argv:
             # remove currency information for a clean migration
             kwargs['default_currency'] = ''
             kwargs['currency_choices'] = []
['InvenTree/InvenTree/fields.py']