Be sure to import UserSerializer

docs/tutorial/4-authentication-and-permissions.md

@@ -76,6 +76,10 @@ We'll also add a couple of views.  We'd like to just use read-only views for the
         queryset = User.objects.all()
         serializer_class = UserSerializer
         
+Make sure to also import the `UserSerializer` class
+
+	from snippets.serializers import UserSerializer
+
 Finally we need to add those views into the API, by referencing them from the URL conf.
 
     url(r'^users/$', views.UserList.as_view()),