makemigrations should create empty migrations dir for any installed app without it

[Andriy Sokolovskiy]

Since django is not supporting apps without migrations in master, makemigrations should create empty migrations dir for any installed app without it, because it is ignoring applications if one use manage.py makemigrations without explicit providing of application name.

[Tim Graham]

But don't create a migrations directory unless the app has models.

[Markus Holtermann]

We haven't really deprecated apps without migrations (no deprecation warning in either 1.7 or 1.8). Although we have documented it I'm not sure we can make the change for 1.9.

We also need to figure out a way of how to run the tests without explicit migrations. Once we're there I think we're ready for apps without migrations.

[Markus Holtermann]

After a talk with Andrew at DjangoCon Europe:

Given #24481 and how that plays in with our test apps, we might reconsider dropping support for apps without migrations.

At some point (2.0 would be a good candidate to justify increasing the major version number ;) ) we should automatically create the migrations package.

[Andriy Sokolovskiy]

After discussion with Markus, we should postpone this until the result of #24481