title: Django-crispy-forms: set CSS class for AppendedText parent div
body: <p><strong>Forms:</strong></p>
  
  <pre><code>class StartEndDateEpayOperatorsForm(forms.Form):
  
      ...
  
      def __init__(self, *args, **kwargs):
          super(StartEndDateEpayOperatorsForm, self).__init__(*args, **kwargs)
          self.helper = FormHelper()
  
          ...
  
          self.helper.layout = Layout(
              AppendedText('start_date', '&lt;span class="glyphicon glyphicon-calendar"&gt;&lt;/span&gt;', active=True, css_class='date'),
              ...
          )
  </code></pre>
  
  <p><strong>Form HTML:</strong></p>
  
  <p><img src="https://i.stack.imgur.com/oKogg.png" alt="Example"></p>
  
  <pre><code>        ...
          &lt;div class="input-group"&gt;
              &lt;input id="id_start_date" type="text" class="date dateinput form-control" value="2013-10-01" name="start_date"&gt; 
              &lt;span class="input-group-addon active"&gt;
                  &lt;span class="glyphicon glyphicon-calendar"&gt;&lt;/span&gt;
              &lt;/span&gt;
           &lt;/div&gt;
          ...
  </code></pre>
  
  <p>In order to use calendar icon as <em>bootstrap-datepicker</em> trigger <strong>I need to add new class <em>date</em> to the <em><code>&lt;div class="input-group"&gt;</code></em></strong>.</p>
  
  <p>How can I achieve it with <em>django-crispy-forms</em>?</p>
  
  <p>At the moment the <em>AppendedText</em>'s attribute <em>css_class</em> aplying to the INPUT element not the parent DIV.</p>
  
  <p>Tnx!</p>