Merge pull request #180 from monomaniar/master

Miss import django.HttpResponse.

Author: masci

docs/tutorial/tutorial_02.rst

@@ -19,6 +19,7 @@ your `views.py` module and import the view:
 .. code-block:: python
 
     from oauth2_provider.views.generic import ProtectedResourceView
+    from django.http import HttpResponse
 
 Then create the view which will respond to the API endpoint:
 
@@ -61,4 +62,4 @@ Try performing a request and check that your :term:`Resource Server` aka :term:`
 an HTTP 200.
 
 :doc:`Part 3 of the tutorial <tutorial_03>` will show how to use an access token to authenticate
-users.
+users.