Fix #611

Minor but confusing typo in tutorial.

docs/tutorial/dbinit.rst

@@ -32,7 +32,7 @@ add the following lines to your existing imports in `flaskr.py`::
 Next we can create a function called `init_db` that initializes the
 database.  For this we can use the `connect_db` function we defined
 earlier.  Just add that function below the `connect_db` function in
-`flask.py`::
+`flaskr.py`::
 
     def init_db():
         with closing(connect_db()) as db: