title: Angularjs: Listen to model change in a directive
body: <p>I'm trying to find out how I can listen to when the model is updated within an directive.</p>
  
  <pre><code>eventEditor.directive('myAmount',function(){
      return {
          restrict: 'A',
          link: function(scope, elem, attrs) {
            scope.$watch(attr['ngModel'], function (v) {
              console.log('value changed, new value is: ' + v);
            });
          } 
        } 
      }
  };
  </code></pre>
  
  <p>});</p>
  
  <p>The directive is called within ng-repeat as </p>
  
  <pre><code>&lt;div ng-repeat="ticket in tickets"&gt;
      &lt;input my-amount ng-model="ticket.price"&gt;&lt;/input&gt; 
  &lt;/div&gt;
  </code></pre>
  
  <p>Very happy for any help. I don't understand how the scope attribute looks like within an ng-repeat.</p>
  
  <p>Thanks.</p>