title: Adding & Removing additional class on my element tag
body: <p>I'm learning Angular.js and at first glimpse I thought it was easy. :P. But I'm stuck here. What I want is to add another class on my &lt;.a>(anchor) tag. </p>
  
  <p>My HTML Code:</p>
  
  <pre><code>&lt;a href="#/services" title="Services" class="scroll"&gt;
  &lt;a href="#/portfolio" title="Portfolio" class="scroll"&gt;
  </code></pre>
  
  <p>Say when I click the service link it will add "enabled" class</p>
  
  <pre><code>&lt;a href="#/services" title="Services" class="scroll enabled"&gt;
  &lt;a href="#/portfolio" title="Portfolio" class="scroll"&gt;
  </code></pre>
  
  <p>then if I clicked the portfolio link it will add "enabled" class also and will remove the enabled class from the services anchor tag</p>
  
  <pre><code>&lt;a href="#/services" title="Services" class="scroll"&gt;
  &lt;a href="#/portfolio" title="Portfolio" class="scroll enabled"&gt;
  </code></pre>
  
  <p>What is the best way to achieve this? Read about ng-click and ng-class, and also does ng-class support ternary operator? Their docs doesn't say anything about that. <a href="http://docs.angularjs.org/api/ng.directive%3angClass">link</a></p>