title: Give form a CSS class using simple_form_for
body: <p>Here's what I've tried, and the <code>simple_form_for</code> call ignored my class setting.</p>
  
  <pre><code># Rails code in view:
  &lt;%= simple_form_for @admin_artist, :class =&gt; 'foobarbaz' do |f| %&gt;
  
  # Renders:
  &lt;form accept-charset="UTF-8" action="/admin/artists" class="simple_form new_admin_artist" id="new_admin_artist" method="post" novalidate="novalidate"&gt;
  </code></pre>
  
  <p>Any suggestions?</p>