remove sidekiq reference in readme
remove sidekiq reference in readme

alejandrogarciasalas/classroom,jingruoruchu/classroom,RyanTech/classroom,guoyu07/classroom,jasnow/classroom,chenwenbin928/classroom,tjhorner/classroom,mostlybadfly/classroom,bhanuc/classroom,chengjunjian/classroom,mkcode/classroom,tjhorner/classroom,chengjunjian/classroom,RyanTech/classroom,mostlybadfly/classroom,jasnow/classroom,adoosii/classroom,nfeliciano/classroom,BelieveC/classroom,ConnorCartwright/classroom,jingruoruchu/classroom,bhanuc/classroom,ConnorCartwright/classroom,guoyu07/classroom,chenwenbin928/classroom,alejandrogarciasalas/classroom,ConnorCartwright/classroom,jasnow/classroom,RyanTech/classroom,BelieveC/classroom,chengjunjian/classroom,mostlybadfly/classroom,guoyu07/classroom,nfeliciano/classroom,BelieveC/classroom,nfeliciano/classroom,tjhorner/classroom,adoosii/classroom,hackerkid/classroom,BelieveC/classroom,bhanuc/classroom,jingruoruchu/classroom,mkcode/classroom,alejandrogarciasalas/classroom,adoosii/classroom,hackerkid/classroom,chenwenbin928/classroom,hackerkid/classroom,mkcode/classroom