title: SchemaEditor error when trying runserver
body: <p>I have a MongoDB backend and am running into this error upon <code>python3 manage.py runserver</code>. </p>
  
  <blockquote>
    <p>Traceback (most recent call last):
     File "hct/.local/lib/python3.4/site-packages/Django-1.8.3-py3.4.egg/django/utils/autoreload.py", line 225, in wrapper
        fn(*args, **kwargs)
      File "hct/.local/lib/python3.4/site-packages/Django-1.8.3-py3.4.egg/django/core/management/commands/runserver.py", line 112, in inner_run
        self.check_migrations()
      File "hct/.local/lib/python3.4/site-packages/Django-1.8.3-py3.4.egg/django/core/management/commands/runserver.py", line 164, in check_migrations
        executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
      File "hct.local/lib/python3.4/site-packages/Django-1.8.3-py3.4.egg/django/db/migrations/executor.py", line 19, in <strong>init</strong>
        self.loader = MigrationLoader(self.connection)
      File "hct/.local/lib/python3.4/site-packages/Django-1.8.3-py3.4.egg/django/db/migrations/loader.py", line 47, in <strong>init</strong>
        self.build_graph()
      File "hct/.local/lib/python3.4/site-packages/Django-1.8.3-py3.4.egg/django/db/migrations/loader.py", line 182, in build_graph
        self.applied_migrations = recorder.applied_migrations()
      File "hct/.local/lib/python3.4/site-packages/Django-1.8.3-py3.4.egg/django/db/migrations/recorder.py", line 59, in applied_migrations
        self.ensure_schema()
      File "hct/.local/lib/python3.4/site-packages/Django-1.8.3-py3.4.egg/django/db/migrations/recorder.py", line 52, in ensure_schema
        with self.connection.schema_editor() as editor:
      File "hct/.local/lib/python3.4/site-packages/Django-1.8.3-py3.4.egg/django/db/backends/base/base.py", line 503, in schema_editor
        'The SchemaEditorClass attribute of this database wrapper is still None')
    NotImplementedError: The SchemaEditorClass attribute of this database wrapper is still None</p>
  </blockquote>
  
  <p>I've made just the following changes in settings.py -</p>
  
  <p>In installed apps, added</p>
  
  <blockquote>
    <p>'djangotoolbox',</p>
  </blockquote>
  
  <p>db configuration in settings.py -</p>
  
  <pre><code>DATABASES = {
  'default': {
      'ENGINE': 'django_mongodb_engine',
      'NAME': 'dbname',
      'HOST': 'dbhost',
      'USER': 'dbuser',
      'PASSWORD': 'dbpw'
  }
  </code></pre>
  
  <p>}</p>
  
  <p>I have the following 3 mongodb packages installed in site-packages</p>
  
  <ul>
  <li>django-mongodb-engine (from <a href="https://github.com/django-nonrel" rel="nofollow">https://github.com/django-nonrel</a>)</li>
  <li>djangotoolbox</li>
  <li>pymongo</li>
  </ul>
  
  <p>In case the following are relevant,</p>
  
  <ul>
  <li>My models.py isn't fully populated yet.</li>
  <li>If I run <code>django-admin runserver --settings = myproject.settings</code>, it raises </li>
  </ul>
  
  <blockquote>
    <p>ImportError: No module named 'myproject'</p>
  </blockquote>
  
  <p>Project folder is as follows-</p>
  
  <p>myproject</p>
  
  <ul>
  <li><p>myproject</p>
  
  <ul>
  <li>settings.py</li>
  <li>wsgi.py</li>
  </ul></li>
  <li><p>myapp</p>
  
  <p>manage.py</p></li>
  </ul>
  
  <p>I'm not sure if I need to install any other package from <a href="https://github.com/django-nonrel" rel="nofollow">https://github.com/django-nonrel</a> (in addition to mongodb-engine-master)</p>