title: What is the correct button_to syntax for adding a class to the generated form?
body: <p>I'm trying to apply a class to the form generated by button_to in Rails 3.</p>
  
  <p>The <code>:class</code> option sets the class for the submit button so the <a href="http://apidock.com/rails/v3.1.0/ActionView/Helpers/UrlHelper/button_to">docs</a> tell us to use <code>:form_class</code> to apply a class to the form. </p>
  
  <p>E.g.</p>
  
  <pre><code>&lt;%= button_to 'x', user_contact_path(@user, contact), :method =&gt; :delete, :form_class =&gt; "delete" %&gt;
  </code></pre>
  
  <p>This just adds the attribute <code>form_class="delete"</code> to the button element. I've tried various combinations using <code>:html_options</code> and so on. </p>
  
  <p>Anybody know how to do this?</p>