title: hiding an option in ng-options
body: <p>I'm pretty new to Angular and trying the ng-options.  In my controller, I have:</p>
  
  <pre><code>$scope.permissionLevels = [
      { value: "ROLE_READ", text: "Read Only" },
      { value: "ROLE_WRITE", text: "Write" }
  ];
  </code></pre>
  
  <p>In my template, I have:</p>
  
  <pre><code>&lt;select ng-options="permissionLevel.text for permissionLevel in permissionLevels"
          ng-model="selectedValue"&gt;&lt;/select&gt;
  </code></pre>
  
  <p>Depending on the view, I want to hide either Read or Write.  So in my controller, I have another flag that indicates what view it is.  Before I used ng-options, I had a normal select drop down and did something like this:</p>
  
  <pre><code>&lt;select&gt;
      &lt;option&gt;Read Only &lt;/option&gt;
      &lt;option ng-show="shouldShowWrite"&gt;Write &lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>Is there a way to do this with ng-options?  Thanks.</p>