Fixed user exists bug and added new success messages (#2510)
Fixed user exists bug and added new success messages (#2510)


Submitty/Submitty,Submitty/Submitty,RCOS-Grading-Server/HWserver,Submitty/Submitty,Submitty/Submitty,RCOS-Grading-Server/HWserver,Submitty/Submitty,RCOS-Grading-Server/HWserver,RCOS-Grading-Server/HWserver,RCOS-Grading-Server/HWserver,Submitty/Submitty,RCOS-Grading-Server/HWserver,Submitty/Submitty,Submitty/Submitty,RCOS-Grading-Server/HWserver,Submitty/Submitty,RCOS-Grading-Server/HWserver,RCOS-Grading-Server/HWserver