Fix title

lib/views/layout/2column.html

@@ -20,7 +20,7 @@
     <footer class="">
       <p>
       <a href="" data-target="#help-modal" data-toggle="modal"><i class="fa fa-question-circle"> ヘルプ</i></a>
-      &copy; {{ now|date('Y') }} {{ config.crowi['app:title'] }} <img src="/logo/100x11_g.png" alt="powered by Crowi"> </p>
+      &copy; {{ now|date('Y') }} {{ config.crowi['app:title']|default('Crowi') }} <img src="/logo/100x11_g.png" alt="powered by Crowi"> </p>
     </footer>
   </div>
 </aside>