title: Django Rest Framework M2M Through Model field not resolving
body: <p>Here are my models</p>
  
  <pre><code># Models
  class Category(models.Model):
      parent = models.ForeignKey('Category', null=True, blank=True, related_name="children")
      name = models.CharField(max_length=64)
      alternate_naming = models.ManyToManyField('businesses.Office', through='CategoryOfficeNaming', blank=True)
  
  
  class CategoryOfficeNaming(models.Model):
      category = models.ForeignKey('Category')
      office = models.ForeignKey('businesses.Office')
      name = models.CharField(max_length=64)
  </code></pre>
  
  <p>And here are my serializers</p>
  
  <pre><code># Serializers
  class CategoryOfficeNamingSerializer(serializers.ModelSerializer):
      class Meta:
          model = CategoryOfficeNaming
          fields = (
              'office',
              'name',
          )
  
  
  class CategorySerializer(serializers.ModelSerializer):
      # We need special recursive serialization here for Category (parent) -&gt; Category (child) relationship
      children = serializers.ListSerializer(read_only=True, child=RecursiveField())
      alternate_naming = CategoryOfficeNamingSerializer(many=True)
  
      class Meta:
          model = Category
          fields = (
              'children',
              'name',
              'alternate_naming',
          )
  </code></pre>
  
  <p>I get an error when trying serialize a Category:</p>
  
  <pre><code>AttributeError at /api/categories/
  'Office' object has no attribute 'category'
  </code></pre>
  
  <p>It seems like the Serializer (alternate_naming) points to an Office instance instead of using the through model (CategoryOfficeNaming) -- why is that? I'm probably doing something silly!</p>