title: Custom constraint validation error doesn't display next to field in Symfony2
body: <p>I am using FOSUserBundle in my Symfony2 project. I added 'birthday' field in User entity, because it is required in registration form. I also added a proper field (type=birthday) to the registration form. I have to check if age of a user is above 18. I prepared my own Constraint for this following <a href="http://symfony.com/doc/2.0/cookbook/validation/custom_constraint.html" rel="nofollow">this tutorial</a>. Everything works perfectly, but error message is attached to form not to field, and I want error message next to field. Instead I get it above the whole form. Every other error in form is displayed next to a proper field. Does anybody know how to force constraint to be attached to the field, not to the form?</p>
  
  <p>EDIT: </p>
  
  <p>Twig code fragment which renders this particular field:</p>
  
  <pre><code>&lt;div class="grid_8" style="margin-bottom:20px;"&gt;
        &lt;div class="grid_2 alpha"&gt;{{ form_label(form.date_of_birth)}}&lt;/div&gt;
        &lt;div class="grid_4"&gt;{{ form_widget(form.date_of_birth)}}&lt;/div&gt;
        &lt;div class="grid_2 omega"&gt;{{ form_errors(form.date_of_birth)}}&lt;/div&gt;
  &lt;/div&gt; 
  </code></pre>
  
  <p>At the begining of the form I also have:</p>
  
  <pre><code>&lt;div class="grid_8"&gt;
    {{form_errors(form)}}
  &lt;/div&gt;
  </code></pre>