title: Add inline model to django admin site
body: <p>I have these two models:</p>
  
  <pre><code>class Rule(models.Model):
      name = models.CharField(max_length=200)
  
  class Channel(models.Model):
  
      id = models.CharField(max_length=9, primary_key=True)
      name = models.CharField(max_length=100)
      rule = models.ForeignKey(Rule, related_name='channels', blank=True)
  </code></pre>
  
  <p>And I have to be able to add channels to rule in admin site within RuleAdmin interface. So I created these two admin models:</p>
  
  <pre><code>class ChannelAdmin(admin.TabularInline):
      model = Channel
  
  class RuleAdmin(admin.ModelAdmin):
      model = Rule
      inlines = [ChannelAdmin]
  </code></pre>
  
  <p>But when I start my server I got this errors:</p>
  
  <pre><code>ERRORS:
  &lt;class 'main.admin.ChannelAdmin'&gt;: (admin.E202) 'main.Channel' has no ForeignKey to 'main.Channel'.
  </code></pre>
  
  <p>Still in django shell I can make queries like</p>
  
  <pre><code>rule = Rule.objects.get(pk=1)
  rule.channels.all()
  </code></pre>
  
  <p>There is got to be something obvious but I just can't figure it out.</p>