Add missing csrf_token in AdminRenderer post form.

rest_framework/templates/rest_framework/admin.html

@@ -166,6 +166,7 @@
       <form action="{{ request.get_full_path }}" method="POST" enctype="multipart/form-data" class="form-horizontal" novalidate>
         <div class="modal-body">
           <fieldset>
+            {% csrf_token %}
             {{ post_form }}
           </fieldset>
         </div>