title: Auth violation while using a CakePHP plugin model inside a different plugin's controller
body: <p>I am using a UsersController and trying to access a method on that model in another plugins controller:</p>
  
  <pre><code>if ($this-&gt;User-&gt;save($this-&gt;request-&gt;data)) {
      $this-&gt;Discount-&gt;add($this-&gt;request-&gt;data, $this-&gt;User-&gt;getLastInsertID());
  }
  </code></pre>
  
  <p>Than using the uses variable:</p>
  
  <pre><code>public $uses = array('Users.User','AnotherPlugin.Discount');
  </code></pre>
  
  <p>However when I try to save the user, I get an auth violation when trying to call the add method on the Discount model. </p>