Add refresh user function

jupyter/base/values/values.yaml

@@ -21,11 +21,19 @@ hub:
         def __init__(self, *args, **kwargs):
           super().__init__(*args, **kwargs)
           self.user_dict = {}
+
         def pre_spawn_start(self, user, spawner):
           super().pre_spawn_start(user, spawner)
           access_token = self.user_dict[user.name]['access_token']
-              # refresh_token = self.user_dict[user.name]['refresh_token']
           spawner.environment['NEXTCLOUD_ACCESS_TOKEN'] = access_token
+
+        async def refresh_user(self, user, handler=None):
+          access_token = self.user_dict[user.name]['access_token']
+          refresh_token = self.user_dict[user.name]['refresh_token']
+          token_response = self.user_dict[user.name]['token_response']
+          print(token_response)
+          return True
+
       c.JupyterHub.authenticator_class = NextcloudOAuthenticator
       c.NextcloudOAuthenticator.client_id = os.environ['NEXTCLOUD_CLIENT_ID']
       c.NextcloudOAuthenticator.client_secret = os.environ['NEXTCLOUD_CLIENT_SECRET']