title: Mongodb create index with flask mongokit extension
body: <p>I'm trying to create an index with a flask-mongokit connection:</p>
  
  <pre><code>db = MongoKit(app)
  db.mydatabase.users.create_index("email", unique=True)
  </code></pre>
  
  <p>But it throws this error at me:</p>
  
  <pre><code>...
  host=ctx.app.config.get('MONGODB_HOST'),
  AttributeError: 'NoneType' object has no attribute 'app'
  </code></pre>
  
  <p>If I use Pymongo directly instead:</p>
  
  <pre><code>conn = MongoClient()
  conn.mydatabase.users.create_index("email", unique=True)
  </code></pre>
  
  <p>Everithing works fine!</p>
  
  <p>The problem is that I don't want to manage a pymongo's connection but instead use the one created by the mongokit extension.</p>