title: Backbone.js collection fetch not setting response objects as models
body: <p>When fetching a collection, my api response has 10 objects, but the resulting Backbone collection only has 1 model with an attributes array containing the 10 response objects....to put it another way, the fetch is not creating models out of the objects in my response...and I don't know why.</p>
  
  <p>Model definition:</p>
  
  <pre><code>MyApp.Item = Backbone.Model.extend({
      initialize: function(){
  
      }
  });
  </code></pre>
  
  <p>Collection definition:</p>
  
  <pre><code>MyApp.ItemCollection = Backbone.Collection.extend({
      model: MyApp.Item,
      url: '/api/v1/item/',
      parse : function(response){
          //api returns objects in the content attribute of response, need to override parse
          return response.content;  
      }
  });
  </code></pre>
  
  <p>Calling fetch:</p>
  
  <pre><code>var myCollection = new MyApp.ItemCollection();
  
  myCollection.fetch({
      traditional: true,
      data: {  //url params for api call
          u_id: currentUser.id,
          order: 'sort_date:desc',
          start: 0,
          num_items: 10,
          format:'json'}
      });
  </code></pre>
  
  <p>Results:</p>
  
  <p><strong>console.log(response.content);</strong></p>
  
  <pre><code>4571221007823F95BAAFB2BDF81111XX: Object
  0124207763051005AAF59694458EBFXX: Object
  3324207755431003B589CEF237DBE1XX: Object
  3470000061641005BFB5D9983156E0XX: Object
  3515553061641005A02884677F5624XX: Object
  3526033426761006AFEA9852B0DDB5XX: Object
  21431252714010079E4D8413429DB0XX: Object
  26570547220410068F60D1B07D2E08XX: Object
  37557124663710079DDC81EE855981XX: Object
  0152243312031007957B94F5073B69XX: Object
  
  //api successfully returns an array of objects, with GUID as key
  </code></pre>
  
  <p><strong>console.log(myCollection);</strong></p>
  
  <pre><code>r {length: 1, models: Array[1], _byId: Object}
  
  //why only one model? why not 10?
  </code></pre>
  
  <p><strong>console.log(myCollection.models[0].attributes);</strong></p>
  
  <pre><code>4571221007823F95BAAFB2BDF81111XX: Object
  0124207763051005AAF59694458EBFXX: Object
  3324207755431003B589CEF237DBE1XX: Object
  3470000061641005BFB5D9983156E0XX: Object
  3515553061641005A02884677F5624XX: Object
  3526033426761006AFEA9852B0DDB5XX: Object
  21431252714010079E4D8413429DB0XX: Object
  26570547220410068F60D1B07D2E08XX: Object
  37557124663710079DDC81EE855981XX: Object
  0152243312031007957B94F5073B69XX: Object
  __proto__: Object
  
  //there they are...but why?  
  </code></pre>
  
  <p>How can I change the fetch to get these objects added as individual models in myCollection?</p>