title: Style CheckboxSelectMultiple form field. Django
body: <p>I have a form which has one checkboxselectmultiple field:</p>
  <pre><code>class CreateRecipeForm(forms.ModelForm):
      class Meta:
          model = Recipe
          fields = ('name', 'image', 'description', 'cooking_time', 'tags')
          widgets = {
              ...
              'tags': forms.CheckboxSelectMultiple(),
              ...
          }
  </code></pre>
  <p>I can iterate through field's options like:</p>
  <pre><code>{% for option in form.tags %}
  {{ option.tag }} {{ option.choice_label }}
  {% endfor %}
  </code></pre>
  <p>How would I render <code>{{ option.tag }}</code> as an input field? i.e:</p>
  <pre><code>&lt;input type=&quot;checkbox&quot;...&gt;
  </code></pre>
  <p>Thanks.</p>