title: Pass variable from callback function in component to template
body: <p>I've uploaded a file with ember-cli-dropzone (<a href="https://www.npmjs.com/package/ember-cli-dropzonejs" rel="nofollow">https://www.npmjs.com/package/ember-cli-dropzonejs</a>). This works fine. Now i need to update my template with the filename. </p>
  
  <p>Inside a component I have the filename in a callback function. But now i need to pass this to the routes setupController function. So i can use the controller.set, as shown below.</p>
  
  <p>The component JS:</p>
  
  <pre><code>export default Ember.Component.extend({
    actions: {
     submit: function(){
       this.sendAction('action', this.submission);
     }
   },
   uploadSuccess: function(file, response) {
     if (response == '200') {
      return file.name;
     }
   }
  });
  </code></pre>
  
  <p>setupController inside the route:</p>
  
  <pre><code>setupController: function(controller, model){
      var submission = this.store.createRecord('submission', { filter: { assignment_id: model.id } });
  
      submission.filename = filenamePlease; 
      controller.set('submission', submission);
  
  }
  </code></pre>
  
  <p>compenent inside template:</p>
  
  <pre><code>{{submission-form submission=submission user=user action='createSubmission'}}
  </code></pre>
  
  <p>component HBS:</p>
  
  <pre><code>&lt;form {{action 'submit' on='submit'}}&gt;
    {{drop-zone url='http://localhost:4200/api/uploads' success=uploadSuccess}}
    {{input type="hidden" value=submission.filename}}
    &lt;button class="bnt" type="submit"&gt;{{buttonLabel}}&lt;/button&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>How do i get the corresponding template to update after the file has uploaded and uploadSuccess has returned the filename?</p>