title: belongsTo and hasMany not loading in the template
body: <p>I have these models:</p>
  
  <pre><code>export default DS.Model.extend({
    uid: DS.attr('number'),
    name: DS.attr('string'),
    fullName: DS.attr('string'),
    description: DS.attr('string'),
    homepage: DS.attr('string'),
    owner: DS.attr('string'),
    private: DS.attr('boolean'),
    organization: DS.belongsTo('organization', { async: true })
  });
  </code></pre>
  
  <p>and</p>
  
  <pre><code>export default DS.Model.extend({
    uid: DS.attr('number'),
    avatar: DS.attr('string'),
    blog: DS.attr('string'),
    company: DS.attr('string'),
    login: DS.attr('string'),
    location: DS.attr('string'),
    rooms: DS.hasMany('room', { async: true })
  });
  </code></pre>
  
  <p>in the Ember Inspector I can see the whole data:</p>
  
  <p><a href="https://i.stack.imgur.com/NjvP9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NjvP9.png" alt="enter image description here"></a></p>
  
  <p>both rooms and organizations</p>
  
  <p>when I try to show them in my template:</p>
  
  <pre><code>&lt;div class="row"&gt;
      &lt;ul id="room-list"&gt;
        {{#each model key="uid" as |room|}}
          &lt;li&gt;
            &lt;label&gt;{{room.uid}}: {{room.name}} ({{room.organization.name}}) &lt;/label&gt;
          &lt;/li&gt;
        {{/each}}
      &lt;/ul&gt;
    &lt;/div&gt;
  </code></pre>
  
  <p>the <code>()</code> where organization's name should be, is empty, like <code>53415342: PredictionIO-Enterprise ()</code></p>
  
  <p>Here is my serializer</p>
  
  <pre><code>import DS from 'ember-data';
  import Ember from 'ember';
  
  export default DS.JSONSerializer.extend({
    primaryKey: 'uid'
  });
  </code></pre>
  
  <p>and my server response on <code>/organizations/{uid}</code> is</p>
  
  <pre><code>{
    "uid": 1247016,
    "createdAt": 1470496909124,
    "name": "Tweek",
    "avatar": "https://avatars.githubusercontent.com/u/1247016?v=3",
    "blog": "http://tweek.tv",
    "company": null,
    "login": "Ubertweek",
    "location": "Berlin, Germany",
    ....
  </code></pre>