Scenario:
  You have a long-running branch to upgrade your existing codebase to django 1.7.
  You've previously used south, and your existing deployment includes schema changes since the
  base of the django-1.7 upgrade branch.

  You need to re-create django (core) migrations periodically since you can't merge
  south migrations into core migrations.

  (Assumes commands are run from root of project and that apps are top-level directories  Adjust pathing if that is not the case.)