Record score about beer-tally-telegram-bot

[mauvqz]

Achim:

Right now a score is tied to a day (and the notion of a day depends on the timezone of the server) which might not be optimal. Maybe we can have something like record sessions, where a session ends either when all players have recorded their score or when the /end_session command is called.

I agree with this comment, we should be able to start/end a session of recording. The only issue with this is that if anyone is able to start/end a session, then we open ourselves to user errors where a session is ended before it should be. If this is not a problem, then we can proceed as mentioned in the quote. Otherwise we should assign some sort of "session master" where whoever starts the session, is the only one allowed to close it.