title: Group form fields in Symfony2
body: <p>I want to group fields in symfony2. For example wrap them in a div and place headlines in between:</p>
  
  <pre><code>&lt;form&gt;
  &lt;div class="step-1"&gt;
      &lt;h3&gt;Step 1&lt;/h3&gt;
      Field 1
      Field 2
  &lt;/div&gt;
  &lt;div class="step-2"&gt;
      &lt;h3&gt;Step 2&lt;/h3&gt;
      Field 3
      Field 4
  &lt;/div&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>The problem is the form got very much fields so i cant render them one by one in the template. Isnt there any option when adding fields? Like:</p>
  
  <pre><code>$form = $this-&gt;createFormBuilder()
          -&gt;addGroup('step-1')
  </code></pre>
  
  <p>Or how can i handle this?</p>