title: Backbone Marionette : Add a model (and render its view) to a nested Composite View
body: <p>If you don't want to see the complete code, here is what I am trying to do. 
  I have multiple pages and each page has multiple tags. There is a composite View called PageManyView for rendering pages which called its childView PageView. Page View is a nested composite view which renders tags, passing this.model.get('tags') as collection.</p>
  
  <p>Now I can easily add a new page by using pages.add(newPage). Here pages is the collection. <strong>I am facing problem in adding a new Tag</strong>. How can I do that. Please help.</p>
  
  <p><strong>CODE</strong></p>
  
  <pre><code>var PageModel = Backbone.Model.extend({});
  
  var PageCollection = Backbone.Collection.extend({
      model: PageModel
  });
  </code></pre>
  
  <p>My JSON at /data endpoint is coming like this</p>
  
  <pre><code>[
    {
      _id: '1', 'name': '1', info: 'Page 1',
       tags: [{name:'main', color:'red'}, {name:'page', color:'blue'}]
    },
    {
      _id: '1', 'name': '2', info: 'Page 2',
       tags: [{name:'section', color:'blue'} {name:'about', color:'yellow'}]
    }
  ]
  </code></pre>
  
  <p>I have created Nested Views in Marionette like this:</p>
  
  <pre><code>TagView = Marionette.ItemView.extend({
     template: '#tagOneTemplate'
  });
  
  PageView = Marionette.CompositeView.extend({
      template: '#pagesTemplate',
      childViewContainer: 'div.tags',
      childView: EntityViews.TagView,
      initialize: function(){
          var tags = this.model.get('tags');
          this.collection = new Backbone.Collection(tags);
      }
  });
  
  PageManyView = Marionette.CompositeView.extend({
       template: '#pageManyTemplate',
       childView: EntityViews.PageView,
       childViewContainer: 'div#all-pages'
  });
  </code></pre>
  
  <p>Now here is where i am facing problem. Inside Controller of my application, lets say if I have to add a new page</p>
  
  <pre><code>showPages: function(){
     //Getting pages by using jQuery deferred
      var view = PageMainView({collection:pages});
      view.on("add:page", function(){
         var newPage = Page({_id: 3});
         pages.add(newPage);
      });
  
  }
  </code></pre>
  
  <p>Now this add function renders the new page automatically. </p>
  
  <p><strong>BUT I AM FACING PROBLEM IN ADDING a NEW TAG. HOW CAN I ADD A NEW TAG?</strong></p>