Added error message to index.
Added error message to index.

0xfoo/flask-todolist,guillaumededrie/flask-todolist,guillaumededrie/flask-todolist,0xfoo/flask-todolist,polyfunc/flask-todolist,guillaumededrie/flask-todolist,rtzll/flask-todolist,rtzll/flask-todolist,rtzll/flask-todolist,polyfunc/flask-todolist,rtzll/flask-todolist,polyfunc/flask-todolist,0xfoo/flask-todolist