Update user detail API to add last_login

lms/djangoapps/api_manager/users/tests.py

@@ -434,6 +434,7 @@ class UsersApiTests(ModuleStoreTestCase):
         self.assertEqual(response.data['first_name'], self.test_first_name)
         self.assertEqual(response.data['last_name'], self.test_last_name)
         self.assertEqual(response.data['is_active'], True)
+        self.assertIsNotNone(response.data['last_login'])
         self.assertEqual(len(response.data['resources']), 2)
 
     def test_user_detail_get_undefined(self):

lms/djangoapps/api_manager/users/views.py

@@ -89,6 +89,7 @@ def _serialize_user(response_data, user):
     response_data['is_active'] = user.is_active
     response_data['created'] = user.date_joined
     response_data['is_staff'] = user.is_staff
+    response_data['last_login'] = user.last_login
     return response_data