title: Directive's view doesn't reflect model changes
body: <p>I'm trying to figure out why directive's controller doesn't update data</p>
  
  <pre><code>angular.module('sample', [])
  .directive('countdown', function () {
  
  function CountdownController() {
      var countdownController = this;
  
      countdownController.digit = 5;
  
      setTimeout(function () {
          console.log('fired');
          countdownController.digit = 200;
      }, 3000);
  
  }
  
  
  return {
      restrict: 'E',
      controller: CountdownController,
      controllerAs: 'countdownController',
      bindToController: true,
      template: '{{countdownController.digit}}'
  }
  });
  </code></pre>
  
  <p><a href="https://jsfiddle.net/mghs52my/" rel="nofollow">https://jsfiddle.net/mghs52my/</a></p>
  
  <p>I know I can use $scope.$apply() to force changes, but why should I do that?</p>