title: Adding attributes into Django Model's Meta class
body: <p>I'm writing a mixin which will allow my Models to be easily translated into a deep dict of values (kind of like .values(), but traversing relationships). The cleanest place to do the definitions of these seems to be in the models themselves, a la:</p>
  
  <pre><code>class Person(models.Model, DeepValues):
      name = models.CharField(blank=True, max_length=100)
      tribe = models.ForeignKey('Tribes')
  
      class Meta:
          schema = {
              'name' : str,
              'tribe' : {
                  'name' : str
              }
          }
  
  Person.objects.all().deep_values() =&gt; {
      'name' : 'Andrey Fedorov',
      'tribe' : {
          'name' : 'Mohicans'
      }
  }
  </code></pre>
  
  <p>However, Django complains about my including this in <code>class Meta</code> with:</p>
  
  <pre><code>TypeError: 'class Meta' got invalid attribute(s): schema
  </code></pre>
  
  <p>(entire stack trace <a href="http://gist.github.com/76cef1f8aea0ce92cb24" rel="noreferrer">here</a>)</p>
  
  <p>Now, I suppose I could elaborately override this in my mixin, but is there a more elegant way of storing this information?</p>