title: Ember ApplicationController inject not working
body: <p>I'm using Ember CLI 2.5.0. I have the below two controllers. I would like the pages controller to call a method or an action (either will do) in the ApplicationController.</p>
  
  <p>However, I keep getting the error "ReferenceError: application is not defined"</p>
  
  <p>I have tried using the older "needs" API. I tried the even older "controllerFor" method. I tried accessing the App directly and digging down to the controller. I was initially having issues calling this from within a promise and trying to use the "this" keyword, but got around that by declaring a locally scoped var. Nothing seems to be working. I feel like I am missing something simple as all of the aforementioned methods seemed to have worked for others.</p>
  
  <p><strong>In app/controllers/application.js:</strong></p>
  
  <pre><code>import Ember from 'ember';
  
  export default Ember.Controller.extend({
      actions: {
          showModal: function(name, model) {
              this.displayModal(name, model);
          },
          removeModal: function() {
              this.disconnectOutlet({
                  outlet: 'modal',
                  parentView: 'application'
              });
          }
      },
      displayModal: function(name, model) {
          console.log(model);
          this.render(name, {
              into: 'application',
              outlet: 'modal',
              model: model
          });
      }
  });
  </code></pre>
  
  <p><strong>In app/controllers/pages.js:</strong></p>
  
  <pre><code>import Ember from 'ember';
  
  export default Ember.Controller.extend({
      application: Ember.inject.controller(),
      actions: {
          editPageFields: function(page) {
              page.get('fieldValues').then(function(){
                  application.displayModal('page-edit-fields-modal', page);
              });
          }
      }    
  });
  </code></pre>