title: adding a collection to another collection in backbone.js
body: <p>Is it possible to add a collection as the model for a different collection in backbone.js?</p>
  
  <p>I have something like this:</p>
  
  <pre><code>var Stroke = Backbone.Collection.extend({
    model: Point
  });
  
  var StrokeCollection = Backbone.Collection.extend({
    model: Stroke
  });
  </code></pre>
  
  <p>When I try to add to my stroke collection:</p>
  
  <pre><code>this.strokeCollection.add(new Stroke);
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>TypeError: Object false has no method 'bind'
  </code></pre>