socket.js

emit('room:join', roomId)
emit('room:message', msgText)
emit('room:leave')

on('authError')
on('room:join', function(joinedUserId)
on('room:leave', function(leftUserId) 
on('room:message', function(messageObj)

prof flow:
1. Room create über REST Api, gibt roomId zurück *einmalig*
2. emit('room:open', roomId)
3. emit('room:join', roomId)
4. emit('room:close')