fix template

Author: jettify

demos/polls/aiohttpdemo_polls/templates/index.html

@@ -11,7 +11,7 @@ <h1>Poll admin demo: <a href="/admin">admin page</a></h1>
         {% if questions %}
             <ul>
             {% for question in questions %}
-            <li><a href="{{ url('poll', question_id=question.id) }}">{{ question.question_text }}</a></li>
+            <li><a href="{{ url('poll', question_id=question.id|string) }}">{{ question.question_text }}</a></li>
             {% endfor %}
             </ul>
         {% else %}