More refactoring

cps/templates/shelf_edit.html

@@ -16,7 +16,7 @@
     {% endif %}
     <button type="submit" class="btn btn-default" id="submit">{{_('Submit')}}</button>
     {% if shelf.id != None %}
-      <a href="{{ url_for('show_shelf', shelf_id=shelf.id) }}" class="btn btn-default">{{_('Back')}}</a>
+      <a href="{{ url_for('shelf.show_shelf', shelf_id=shelf.id) }}" class="btn btn-default">{{_('Back')}}</a>
     {% endif %}
   </form>
 </div>