title: Backbone.js Fetching a more complex data and using as a collection
body: <p>Assume I have a such json setting:</p>
  
  <pre><code>{
    page:1,   
    items:[
      {  
        name: 'item1', 
        id:1
      }, 
      {
        name: 'item1', 
        id:2
      }, 
      {
        name: 'item1', 
        id:3
      }
    ] 
  }
  </code></pre>
  
  <p>And a such modelling:</p>
  
  <pre><code>var Item = Backbone.Model.extend({
      defaults: {name:  "No name"}
  });
  
  var ItemCollection = Backbone.Collection.extend({
      model: Item,
      url: '/some/ajax/url',
  });
  </code></pre>
  
  <p>After fetching this json, how can I map the items set as the collection of the ItemCollection and add the page number as an attribute to the collection?</p>