title: angular issue with ng-model object
body: <p>Model object is doesn't iterate by some reason. When i trying to loop of $scope.model it doesn't work... when i select few check-box i need checked ids in console..
  $scope.model is there its dynamic. It is by default empty but if you check some checkboxs it will create. </p>
  
  <p><a href="http://plnkr.co/edit/hPn01mcxjzoHGSwMZQrW?p=preview" rel="nofollow">http://plnkr.co/edit/hPn01mcxjzoHGSwMZQrW?p=preview</a></p>
  
  <pre><code>$scope.model = {}; 
  
    for(var i in $scope.model){
     console.log(i);
     if($scope.model[i]== true){
     console.log("checked id is"+i);
   } 
  </code></pre>