title: Combining angular-ui progressbar with ngClass
body: <p>I would like to combine the directive progress from angular-ui, with the directive ngClass.</p>
  
  <p>So far I don't get any reactions at all. Am I doing this wrong, or is it not possible to combine?</p>
  
  <p>What I want is a progressbar that has the class active when the background process is working, but turns off when it's complete or errnous.</p>
  
  <p>HTML:
  </p>
  
  <pre><code>&lt;progress max="100" percent="progress" class='progress-striped' 
      ng-class='{"active": active}'&gt;&lt;/progress&gt;  
  </code></pre>
  
  <p>JS:
  </p>
  
  <pre><code>$scope.active = true;
  $scope.progress = {value:10, type:"danger"};
  </code></pre>
  
  <p>See my plunkr at <a href="http://plnkr.co/edit/koR0VnTKdpnhhMuD16hl" rel="nofollow">http://plnkr.co/edit/koR0VnTKdpnhhMuD16hl</a></p>
  
  <p>Cheers!</p>