Fix possible user is undefined in realtime events
Fix possible user is undefined in realtime events

ironhack/hackmd,aswathyjacob8/newtest,ironhack/hackmd,hackmdio/hackmd,hackmdio/hackmd,PeterDaveHello/hackmd,Rwing/hackmd,aswathyjacob8/newtest,Yukaii/hackmd,PeterDaveHello/hackmd,ironhack/hackmd,jccrofty30/hackmd,aswathyjacob8/newtest,Yukaii/hackmd,jackycute/HackMD,jackycute/HackMD,jccrofty30/hackmd,Yukaii/hackmd,Rwing/hackmd,PeterDaveHello/hackmd,jccrofty30/hackmd,Rwing/hackmd,hackmdio/hackmd,jackycute/HackMD