Allow override of user authentication logic for API

tailbone/api/auth.py

@@ -82,13 +82,16 @@ class AuthenticationView(APIView):
         if not (username and password):
             return {'error': "Invalid username or password"}
 
-        user = authenticate_user(Session(), username, password)
+        user = self.authenticate_user(username, password)
         if not user:
             return {'error': "Invalid username or password"}
 
         login_user(self.request, user)
         return self.user_info(user)
 
+    def authenticate_user(self, username, password):
+        return authenticate_user(Session(), username, password)
+
     @api
     def logout(self):
         """