Update user guide to mention sort by assignee
Update user guide to mention sort by assignee

Sumei1009/HubTurbo,gaieepo/HubTurbo,saav/HubTurbo,HyungJon/HubTurbo,Sumei1009/HubTurbo,saav/HubTurbo,gaieepo/HubTurbo,HyungJon/HubTurbo