title: django rest framework create nested objects "Models" by POST
body: <p>I'm trying POST a new a Nested Object, the problem is just create the "top" object (Playlist), but don't create the "ChannelItem"...</p>
  
  <p>My Models:</p>
  
  <pre><code>class Playlist(models.Model):
      provider = models.IntegerField()
      channel_id = models.CharField(max_length=100)
      channel_version = models.CharField(blank=True, max_length=100)
      start = models.DateTimeField()
      url = models.CharField(max_length=500)
  
  
  class ChannelItem(models.Model):
      playlist = models.ForeignKey(Playlist, editable=False, related_name='channelitems')
      content_id = models.CharField(max_length=100)
      content_version = models.CharField(blank=True, max_length=100)
  </code></pre>
  
  <p>My Serializer:</p>
  
  <pre><code>class ChannelItemSerializer(serializers.ModelSerializer):
      class Meta:
          model = ChannelItem
          fields = ('content_id', 'content_version')
          exclude = ('id')
          depth = 1
  
  
  class PlaylistSerializer(serializers.ModelSerializer):
  
      class Meta:
          model = Playlist
          fields = ('id', 'provider', 'channel_id', 'channel_version', 'start', 
                    'url', 'channelitems')
          depth = 2
  
  channelitems = ChannelItemSerializer()
  </code></pre>
  
  <p>I use the curl to post the following data :</p>
  
  <pre><code>'{"provider":125,"channel_id":"xyz", "channel_version":"xsqt", 
  "start":"2012-12-17T11:04:35","url":"http://192.168.1.83:8080/maaaaa",
  "channelitems":[{"content_id":"0.flv", "content_version":"ss"},
  {"content_id":"1.flv","content_version":"ss"}]}' http://localhost:8000/playlist_scheduler/playlists/
  </code></pre>
  
  <p>I receive the message:</p>
  
  <pre><code>HTTP/1.1 201 CREATED
  Content-Type: application/json
  Transfer-Encoding: chunked
  Date: Mon, 17 Dec 2012 20:12:54 GMT
  Server: 0.0.0.0
  
  {"id": 25, "provider": 125, "channel_id": "xyz", "channel_version": "xsqt",
  "start":"2012-12-17T11:04:35", "url": "http://localhost:8080/something",
  "channelitems": []}
  </code></pre>