title: Id is lost while trying to JSON.stringify Ember model
body: <p>I'm trying to <code>JSON.stringify()</code> the model of a route inside the controller by using the below code. It works and it returns all model attributes, except for the actual id of the model. Can we receive the id as well?</p>
  
  <pre><code>    var plan = this.get('model');
      var reqBody = JSON.stringify(
                                   {
                                      plan,
                                      token
                                   });
  </code></pre>