Ember数据保存

Question

我在使用Ember应用程序更新模型时遇到了很多麻烦。我似乎无法找到描述如何更新我的应用的好文档。以下代码是我尝试的。这会向/ playlists /：playlist_id发送更新，遗憾的是它也没有发送更新后的歌曲...是否有一些我无法找到的pushObject回调？我试图保存错误的东西吗？

App.PlaylistIndexController = Ember.ObjectController.extend({
  actions: {
    addSong: function(song) {
      songs = this.get('songs');
      songs.pushObject(song);

      this.get('model').save();
    } 
  }
});

App.Playlist = DS.Model.extend({
    name: DS.attr('string'),
    songs: DS.hasMany('song'),
});

App.Song = DS.Model.extend({
  name: DS.attr('string'),
  artist: DS.attr('string'),
  playlist: DS.belongsTo('playlist'),
});