Game start alerts

[robere2]

Lobbies contain messages notifying users of a specific game mode starting soon. It'd be nice if users could toggle to receive these messages wherever they are on the server. There's two ways of doing this:

1. Crowdsourced data
   a. Vulnerable to abuse.
   b. Will only catch messages if a user is in one of the lobbies.
2. Bots
   a. Requires much more server overhead and development time.
   b. Costs money for accounts.
   c. Vulnerable to bot bans.