title: Add more data to existing model (backbone.js)
body: <p>The initial <code>fetch</code> done for a collection retrieves partial details for each model. When the user clicks on an item on the webpage, it will need to retrieve more details for that item and display it to the user. </p>
  
  <p>The API function to return the additional data missing in the initial fetch for that item has already been implemented (<code>/api/full_details</code>).</p>
  
  <p><strong>Problem:</strong> How should I retrieve the additional and append it to the existing model? My understanding is that if I do a <code>model.fetch()</code>, the existing data in that model will be gone. I think that if the <code>fetch()</code> for models have an option <code>{add:true}</code> like the <code>fetch()</code> for collections, that'll be what I need here.</p>
  
  <p><strong>Model</strong></p>
  
  <pre><code>Listing = Backbone.Model.extend({
  });
  </code></pre>
  
  <p><strong>Collection</strong></p>
  
  <pre><code>ListingCollection = Backbone.Collection.extend({
      model: Listing,
      url: '/api/search'
  });
  </code></pre>
  
  <p><strong>View</strong></p>
  
  <pre><code>ListingListView = Backbone.View.extend({ ........ });
  
  ListingView = Backbone.View.extend({
      events: {
          'click': 'getFullDetails'
      },
  
      getFullDetails: function() {
          // What should I do here?
      }
  })
  </code></pre>
  
  <p><strong>Somewhere in the router</strong></p>
  
  <pre><code>this.listingList = new ListingCollection();
  var self = this;
  this.listingList.fetch({
      data: {some:data},
      processData: true,
      success: function() {   
          self.listingListView = new ListingListView({ collection: self.listingListNew });
          self.listingListView.render();
      }
  </code></pre>