Add usersWithRole to the Auth class in auth.coffee
Add usersWithRole to the Auth class in auth.coffee

This allows scripts to list out all users with a specific role by calling robot.auth.usersWithRole
alexchenfeng/hubot,alexchenfeng/hubot,davidkassa/hubot,ykelvis/hubot,codydaig/hubot,eshamow/gutterbot,rafaell-lycan/Hubot-X9,ddmng/brazil82-hubot,Arthraim/merlin,scboucher/hubot,ToriTomyuTomyu/nothing-yet,dopeboy/hubot,armilam/lessonly-bort,zvelo/hubot,fgbreel/hubot,makii42/hubot,scboucher/hubot,cycomachead/hubot,RavenB/hubot,plated/hubot,michaelansel/hubot,edorsey/hubot,iDTLabssl/hubot,hubotio/hubot,Snorlock/hubot,RiddickSky/hubot,skcript/skubot,mujiansu/hubot,bgranberry/hubot,kgrz/hubot,leohmoraes/hubot,wyncode/hubot,poppingtonic/hubot,Hartmarken/hubot,mcanthony/hubot,mchill/hubot,decaffeinate-examples/hubot,nakaearth/myhubot,shinvdu/hubot,PropertyUX/nubot,andrewpong/awp-hubot,sharabash/hubot,GrimDerp/hubot,sdimkov/hubot,daudich/hubot,markstory/hubot,ClaudeBot/hubot,ykusumi/test-hubot,kristenmills/hubot,CobyR/hubot,fstehle/hubot,PropertyUX/nubot,b3nj4m/hubot,lisb/hubot,gregkare/hubot,github/hubot,joshsobota/hubot,blackwellops/hubot,alex-zhang/hubot,msound/hubot,WaleedAshraf/hubot,mjurczyk/hubot,julianromera/hubot,minted/hubot,AlexandrPuryshev/hubot,rayatbuzzfeed/hubot,mutewinter/hubot,craig5/hubot,mrb/hubot,nandub/hubot,vkhang55/hubot,geoffreyanderson/hubot,bradparks/hubot__github_chat_bot,SIOPCO/hubot,ooohiroyukiooo/hubot,PopExpert/hubot,wieden-kennedy/hubot,jschell/hubot,decaffeinate-examples/hubot,lukw00/hubot,brodul/hubot,cameronmcefee/hubot,rlugojr/hubot,markstory/hubot,kkirsche/hubot,melexis/melexis-hubot,PopExpert/hubot,danielcompton/hubot,lisb/hubot,mauricionr/hubot,jasonrhodes/botzero,ToriTomyuTomyu/nothing-yet,github/hubot,ouadie-lahdioui/hubot,krahman/hubot,yujiroarai/hws-hubot,ajayanandgit/hubot,doudoupower/hubot,Mattlk13/Hubot,chadfurman/hubot,alucardzhou/hubot,jianchen2580/hubot,pchaigno/hubot,tiagochiavericosta/hubot,jasonkarns/hubot,rmdelo/appboy-hubot,Drooids/hubot,alexchenfeng/hubot,hcxiong/hubot,hotrannam/hubot,ajschex/hubot,awbauer/hubot,nandub/hubot,alexchenfeng/hubot,keyvanakbary/hubot,andrewpong/awp-hubot,voltsdigital/hubot,lisb/hubot,hubotio/hubot,alexchenfeng/hubot,taojuntjpp/hubot,aslihandincer/hubot,limianwang/hubot,eetuuuu/hubot,howprice/hubot