title: Add css class to rails select helper in haml
body: <p>Simple task. I want to add a css class on my following f.select tag in haml. I have tried this:</p>
  
  <pre><code>.field= f.select :sponsor_id, sponsors.map { |s| [s.name, s.id] }, {:class =&gt; "my-class"}
  </code></pre>
  
  <p>it doesn't throw an exception but also doesn't append the class to the select element. Tried without brackets, also no success.</p>