title: Backbone listenTo not firing
body: <p>I've set up a simple backbone.js app.  Everything is working, except for one particular event.</p>
  
  <p>The part that is not working, is a 'this.listenTo' type of event.  I've never used these type of events before, so I'm sure it's some misunderstanding on my part.</p>
  
  <p>app.js:</p>
  
  <pre><code>new bookView({ 
      model: bookModel
   }).render();
  </code></pre>
  
  <p>bookModel.js : </p>
  
  <pre><code>Backbone.Model.extend({
  
      defaults: function() {
  
          return { sections: new SectionCollection() 
      }
  
  });
  </code></pre>
  
  <p>|</p>
  
  <p>bookView.js :  this is where the event is not firing....</p>
  
  <pre><code>return Backbone.View.extend({
  
      initialize: function() {
  
          this.sections = this.model.get('sections'); 
          this.listenTo(this.sections, 'add', this.addSection);
  
      },
  
      addSection: function() {
                  //never gets here....
          console.log("adding section...");
      }
  
  });
  </code></pre>
  
  <p>Any suggestions?</p>
  
  <p>Thanks!</p>