add user settings

app/templates/common/macros.html

@@ -76,7 +76,7 @@
   {{babycode_editor_component(ta_name, prefill = prefill)}}
   {% if not cancel_url %}
     <span>
-      <input type="checkbox" id="subscribe" name="subscribe" {{ "checked" if session['subscribe_by_default'] else "" }}>
+      <input type="checkbox" id="subscribe" name="subscribe" {{ "checked" if session.get('subscribe_by_default', default=true) else "" }}>
       <label for="subscribe">Subscribe to thread</label>
     </span>
   {% endif %}