BeInvitedToARoom method
被邀请进入一个聊天室
Implementation
Future BeInvitedToARoom(NewRoomEvent event, Member me) async {
rooms.add(event.room);
event.room.members.add(event.member);
event.room.members.add(me);
// TODO: 执行数据库持久化
await _saveRooms();
}