title: Use ActiveModel::Serializers to include two parent json arrays
body: <p>I'm trying to send my front-end application json that looks like this:</p>
  
  <pre><code>{
    facilities: [
       {id: 5, name: 'happy days ranch', location: { address: '1424 Pastoral Lane', zipcode: '25245'}, instructor_ids: [2, 4, 9]}
    ],
    instructors: [
       {id: 4, name: 'Johnny Pheonix', skill: '8', picture: 'aws_url', facility_ids: [5, 8, 12}
    ]
  }
  </code></pre>
  
  <h2>Things I have tried</h2>
  
  <pre><code>render :json =&gt; @facilities 
  </code></pre>
  
  <p>The serializer discovers this.  Yay!  But this does not include any instructors</p>
  
  <pre><code>render :json =&gt; {facilities: @facilities, instructors: @instructors}
  </code></pre>
  
  <p>This gives me an instructors array and  a facilities array, but activeModel::Serializers is not used.</p>
  
  <pre><code>render :json =&gt; [@facilities, @instructors]
  </code></pre>
  
  <p>At first I was excited about this one, because it gave me two arrays, and it used ActiveModel::Serializers.  However, this is what the JSON looked like:</p>
  
  <pre><code>{facilities: [
    {facilities: [
      #my facilities data
    ]},
    {facilities: [
      #my instructor data
    ]}
  ]}
  </code></pre>
  
  <h3>Is what I'm trying to do even allowed by ActiveModel::Serializers?  If so, how?</h3>
  
  <p>Thanks much in advance! </p>