Add the route for list_classes

plugins/webui/interface/urls.py

@@ -7,4 +7,6 @@ urls = (
     (r'test/(.+)$', test),
     (r'test/?$', test),
     (r'show/(.+)$', show_document)
+    (r'list_classes/(.+)$', list_classes),
+    (r'list_classes/?$', list_classes),
 )