title: django.core.exceptions.FieldError: Unknown field(s) (y, b, d, o)
body: <p>I have a model where I have the following architecture</p>
  
  <ul>
  <li>There is Post model</li>
  <li>And there is an answer model for the given post (just like in stack overflow)</li>
  </ul>
  
  <p>Since there are some fields which I do not want the user to populate, I have made a custom form for both of the models. The custom form class is working absolute for the first model i.e. Post Model, but I am getting this strange for the PostAns model. If I remove the <strong>class PostAnsForm</strong> then it works fine. </p>
  
  <pre><code>class PostAns(models.Model):
      created = models.DateTimeField(auto_now_add=True)
      creator = models.ForeignKey(User, blank=True, null=True)
      post = models.ForeignKey(Post)
      body = models.TextField()
      like_count = models.IntegerField(default=0,blank=True,null=True)
      # If we use markdown can remove this if not
      body_html = models.TextField(blank=True)
  
  class PostAnsForm(ModelForm):
  
      class Meta:
          model = PostAns
          fields = ('body')
  </code></pre>
  
  <p>I haven't found a similar error on the net. </p>