title: Add class to ember link-to
body: <p>I try to build a link to a nested route and want to add a class to this link (for twitter bootstrap)</p>
  
  <p>The result should something like this:</p>
  
  <pre><code>&lt; a href="/#/rents/42" class="btn btn-primary btn-small"&gt;do something&lt; /a&gt;
  </code></pre>
  
  <p>First try:</p>
  
  <pre><code>{{#link-to "rent" rent}}
  </code></pre>
  
  <p>gives me a link to the ressource but I cannot specify a (css) class. In the docs I see that only the title attribute can be specified</p>
  
  <p>Second try:</p>
  
  <pre><code>&lt; a href="/#/rents/{{rend.id}}" class="btn btn-primary btn-small"&gt;do something&lt; /a&gt;
  </code></pre>
  
  <p>is also a bad idea, because Ember will add its helper tags [for automatic updates] in the href.</p>
  
  <p>So what can I do?</p>