Add opponent's groupId in BattleToken

[tandotbt]

ArenaService/ArenaService/Repositories/BattleRepository.cs

Line 64 in 2a29215

battle.Entity.Token = _battleTokenGenerator.GenerateBattleToken(battle.Entity.Id);

With availableOpponentId in BattleToken, I can determine how many score a player has gained or lost when winning or losing through TxId.

[Atralupus]

Could you take a look at this? It shouldn’t be too difficult if AddBattleAsync processes the opponent’s information as well.

Additionally, if we’re modifying the token payload, it would be a good idea to include schema versioning. In our case, that would be the payload version.