Add User import. Refs #599

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

@@ -67,6 +67,9 @@ Because `'snippets'` is a *reverse* relationship on the User model, it will not
 
 We'll also add a couple of views to `views.py`.  We'd like to just use read-only views for the user representations, so we'll use the `ListAPIView` and `RetrieveAPIView` generic class based views.
 
+    from django.contrib.auth.models import User
+
+
     class UserList(generics.ListAPIView):
         queryset = User.objects.all()
         serializer_class = UserSerializer