title: Migration urls in app ...has no Migration class
body: <p>When I try to run migration I get  <code>"Migration urls in app *** has no Migration class"</code>? I just added new app.</p>
  
  <p>Have no idea what direction to look. Traceback:</p>
  
  <pre><code>C:\Users\PAPA\DEV\liberty\lib\site-packages\django\db\models\__init__.py:55:
  RemovedInDjango19Warning: The utilities in django.db.models.loading are deprecated 
  in favor of the new application loading system.
  from . import loading
  
  Traceback (most recent call last):   File "manage.py", line 22, in &lt;module&gt;
      execute_from_command_line(sys.argv)
  File "...\django\core\management\__init__.py", line 338, in execute_from_command_line
      utility.execute()
  File "...\django\core\management\__init__.py", line 330, in execute
      self.fetch_command(subcommand).run_from_argv(self.argv)
  File "...\django\core\management\base.py", line 390, in run_from_argv
      self.execute(*args, **cmd_options)
  File "...\django\core\management\base.py", line 441, in execute
      output = self.handle(*args, **options)
  File "...\django\core\management\commands\makemigrations.py", line 63, in handle
      loader = MigrationLoader(None, ignore_no_migrations=True)
  File "...\django\db\migrations\loader.py", line 47, in __init__
      self.build_graph()
  File "...\django\db\migrations\loader.py", line 174, in build_graph
      self.load_disk()
  File "...\django\db\migrations\loader.py", line 109, in load_disk
      "Migration %s in app %s has no Migration class" % (migration_name, app_config.label)
  django.db.migrations.loader.BadMigrationError: Migration urls in app expense has no
  Migration class
  </code></pre>