title: Adding class to Rails select form helper, and multiple selection
body: <p>I am trying to add a class to the select form helper, here is my code:</p>
  
  <pre><code>&lt;%= f.select :manager_id, user.collect {|u| [u.username, u.id]}, :prompt =&gt; "Select manager 
  username", :class =&gt; "btn btn-default dropdown-toggle" %&gt;
  </code></pre>
  
  <p>But it didn't work, and is there an option to add multiple selection?</p>