title: Django queryset get names of model fields
body: <p>I want to get field names of <code>Django</code> model through <code>queryset</code>.</p>
  <p>Models.py:</p>
  <pre><code>class User1(models.Model):
      types1 = (
          ('a', 'a'),
          ('b', 'b'),
          ('c', 'c'),
      )
      types2 = (
          ('a', 'a'),
          ('b', 'b'),
          ('c', 'c'),
      )
      q1 = models.CharField (
          'Today1',
          max_length=200,
          choices=types1, blank=True, null=True, default='---------'
      )
      q2 = models.CharField (
          'Today2',
          max_length=200,
          choices=types2, blank=True, null=False, default='---------',
      )
  </code></pre>
  <p>After <code>queryset</code>, I want to get <code>[q1,q2]</code> or something similar to this but containing only field names.</p>