title: How can I update a DS.Model with response json from store.commit()?
body: <p>Given the models:</p>
  
  <pre><code>Blog.Post = DS.Model.extend({
      title: DS.attr('string'),
      tags:  DS.hasMany('Blog.Tag', { embedded: true })
  });
  
  Blog.Tag = DS.Model.extend({
      foo: DS.attr('string'),
      bar: DS.attr('string')
  });
  </code></pre>
  
  <p>And the instance:</p>
  
  <pre><code>var myPost = Blog.Post.createRecord({ id: 45, title: 'Foo Bar' })
  </code></pre>
  
  <p>When I do <code>myPost.store.commit()</code> (via ember-data's DS.RESTAdapter) my server returns a list of automatically generated tags that should be applied to <code>myPost</code>.  Example response json:</p>
  
  <pre><code>{
    posts: [
      {
        id: 45,
        title: 'Foo Bar',
        tags: [
          { id: 1, foo: 'bar1' },
          { id: 2, foo: 'bar2' }
        ]
      }
    ]
  }
  </code></pre>
  
  <p>I'd expect that <code>myPost</code> would end up with the two tags as returned by the json, but I get this error instead:</p>
  
  <pre><code>Error: &lt;DS.StateManager:ember448&gt; could not respond to event invokeLifecycleCallbacks in state rootState.loaded.updated.uncommitted.
  </code></pre>
  
  <p>What am I doing wrong here?</p>
  
  <p>Edit: clarified json to include ids per @MikeAski's comment. The example given is a simplified version of my actual case--the actual case does include tag ids.</p>