title: Rails 3.1 Formtastic input custom id or class
body: <p>I want to make chain selects part inside my Formtastic form. But is it possible to set custom ids for multiple selects for future AJAX replacement?</p>
  
  <p>This doesn't work:</p>
  
  <pre><code>&lt;%= semantic_form_for [:admin, @production_year] do |f| %&gt;
    &lt;%= f.inputs do %&gt;
      &lt;%= f.input :car_model, :label =&gt; "CarModel", :as =&gt; :select, :collection =&gt; Brand.find(:all, :order =&gt; "name ASC"), :id =&gt; "brand_id" %&gt;
    &lt;% end %&gt;
  &lt;% end %&gt;
  </code></pre>