- Related to https://github.com/ppy/osu-server-spectator/issues/406
Adding this field to this model has several vague reasons that I can't
fully formulate yet, but I can't really see myself going forward
*without* this.
- People were very excited about having referees displayed on the room
participants' list, and so adding the referees as real
`MultiplayerRoomUser`s helps this. Having the role could even be used
client-side to show a special icon or other status on the participants
list. (Which isn't done yet, could be as an aesthetic follow-up after
the basics are in place.)
- Server-side, having this field is convenient for things like
permission checks or just plain logic, as with two hubs you just need to
do different *stuff* on a `MultiplayerRoomUser`.
Bartłomiej Dach