KFet Backends inherit from BaseKFetBackend

Users who authenticate via a KFetBackend got extra select related.
It should save 2 db queries on each request for these users.

kfet/auth/backends.py

@@ -7,7 +7,22 @@ from .utils import get_kfet_generic_user
 User = get_user_model()
 
 
-class KFetBackend(object):
+class BaseKFetBackend:
+    def get_user(self, user_id):
+        """
+        Add extra select related up to Account.
+        """
+        try:
+            return (
+                User.objects
+                .select_related('profile__account_kfet')
+                .get(pk=user_id)
+            )
+        except User.DoesNotExist:
+            return None
+
+
+class KFetBackend(BaseKFetBackend):
     def authenticate(self, request):
         password = request.POST.get('KFETPASSWORD', '')
         password = request.META.get('HTTP_KFETPASSWORD', password)
@@ -20,7 +35,7 @@ class KFetBackend(object):
             return None
 
 
-class GenericTeamBackend(object):
+class GenericTeamBackend(BaseKFetBackend):
     def authenticate(self, username=None, token=None):
         valid_token = GenericTeamToken.objects.get(token=token)
         if username == 'kfet_genericteam' and valid_token: