title: Add css class to select_year helper in Rails (HAML)
body: <p>I want to write this code</p>
  
  <pre><code>&lt;select name="date[birth]" id="date_birth" class = "span1"&gt;
        &lt;option value="2011"&gt;2011&lt;/option&gt;
        &lt;option value="2012" selected="selected"&gt;2012&lt;/option&gt;
        &lt;option value="2013"&gt;2013&lt;/option&gt;
        &lt;/select&gt;
  </code></pre>
  
  <p>in Rails, it has the select_year helper, I just write</p>
  
  <pre><code>= select_year(Date.today, :field_name =&gt; "birth", :start_year =&gt; 2011, :end_year =&gt; 2013)
  </code></pre>
  
  <p>I try to add css class to this by the attribute <code>:class =&gt; "span1"</code>, but it doesn't work!
  Please help me, thanks</p>