title: add template in flash messages symfony2
body: <p>After the create and delete object, I redirect to the same action(indexAction).
  After create I would like render this bootstrap messages as flash messages:</p>
  
  <pre><code>&lt;div class="alert alert-success" role="alert"&gt;
    &lt;a href="#" class="alert-link"&gt;...&lt;/a&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>but after delete, I would like render another block of html:</p>
  
  <pre><code>&lt;div class="alert alert-danger" role="alert"&gt;
    &lt;a href="#" class="alert-link"&gt;...&lt;/a&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>What is the best way to pass this to flash messages?
  Because, I think passing all html is not good idea? </p>
  
  <pre><code>$this-&gt;get('session')-&gt;getFlashBag()-&gt;add(
          'notice',
          '&lt;div class="alert alert-danger" role="alert"&gt;
               &lt;a href="#" class="alert-link"&gt;...&lt;/a&gt;
           &lt;/div&gt;'
      );
  </code></pre>
  
  <p>Is any exist better way to solve this problem?</p>