Implement explicit methods to save and get OAuth2 token and secrets

flask_discord/models/user.py

@@ -189,7 +189,7 @@ class User(DiscordModelsBase):
 
         """
         try:
-            data = {"access_token": session["DISCORD_OAUTH2_TOKEN"]["access_token"]}
+            data = {"access_token": current_app.discord.get_authorization_token()["access_token"]}
         except KeyError:
             raise exceptions.Unauthorized
         return self._bot_request(f"/guilds/{guild_id}/members/{self.id}", method="PUT", json=data) or dict()