title: Receiving error: django.core.exceptions.ImproperlyConfigured
body: <p>I installed Python Social Auth on my vm and tried to run <code>makemigrations</code> and receiving this error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "manage.py", line 10, in &lt;module&gt;
      execute_from_command_line(sys.argv)
    File "/opt/myenv/local/lib/python2.7/site-packages/django/core/management/__init__.py",
  line 338, in execute_from_command_line
      utility.execute()
    File "/opt/myenv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 312,
  in execute
      django.setup()
    File "/opt/myenv/local/lib/python2.7/site-packages/django/__init__.py",
  line 18, in setup
      apps.populate(settings.INSTALLED_APPS)
    File "/opt/myenv/local/lib/python2.7/site-packages/django/apps/registry.py", line 85, 
  in populate
      app_config = AppConfig.create(entry)
    File "/opt/myenv/local/lib/python2.7/site-packages/django/apps/config.py",
  line 127, in create
      "'%s' isn't a subclass of AppConfig." % entry)
  django.core.exceptions.ImproperlyConfigured: 'social.apps.django_app.middleware.SocialAuthExceptionMiddleware'
  isn't a subclass of AppConfig.
  </code></pre>
  
  <p>I ran the same application on my localhost and it's working fine. I cannot understand what this error says. Please help.</p>