Do not allow duplicate usernames
Do not allow duplicate usernames

mrpau/kolibri,learningequality/kolibri,DXCanas/kolibri,mrpau/kolibri,jonboiser/kolibri,benjaoming/kolibri,lyw07/kolibri,benjaoming/kolibri,indirectlylit/kolibri,benjaoming/kolibri,DXCanas/kolibri,jonboiser/kolibri,mrpau/kolibri,indirectlylit/kolibri,jonboiser/kolibri,mrpau/kolibri,learningequality/kolibri,DXCanas/kolibri,learningequality/kolibri,lyw07/kolibri,indirectlylit/kolibri,benjaoming/kolibri,lyw07/kolibri,lyw07/kolibri,jonboiser/kolibri,learningequality/kolibri,indirectlylit/kolibri,DXCanas/kolibri