Adds source id when specifying events.
Adds source id when specifying events.

So that when we add events for testing, we populate source_ids.

wubr2000/zipline,chrjxj/zipline,MonoCloud/zipline,dkushner/zipline,erikness/AlephOne,ronalcc/zipline,enigmampc/catalyst,joequant/zipline,zhoulingjun/zipline,dkushner/zipline,chrjxj/zipline,euri10/zipline,humdings/zipline,sketchytechky/zipline,michaeljohnbennett/zipline,dmitriz/zipline,bartosh/zipline,CDSFinance/zipline,jimgoo/zipline-fork,cmorgan/zipline,grundgruen/zipline,iamkingmaker/zipline,keir-rex/zipline,wilsonkichoi/zipline,CarterBain/AlephNull,ChinaQuants/zipline,dhruvparamhans/zipline,DVegaCapital/zipline,magne-max/zipline-ja,YuepengGuo/zipline,morrisonwudi/zipline,keir-rex/zipline,bartosh/zipline,florentchandelier/zipline,AlirezaShahabi/zipline,CarterBain/AlephNull,kmather73/zipline,alphaBenj/zipline,sketchytechky/zipline,humdings/zipline,davidastephens/zipline,umuzungu/zipline,jimgoo/zipline-fork,wilsonkichoi/zipline,cmorgan/zipline,davidastephens/zipline,euri10/zipline,gwulfs/zipline,DVegaCapital/zipline,enigmampc/catalyst,dmitriz/zipline,quantopian/zipline,mattcaldwell/zipline,jordancheah/zipline,jordancheah/zipline,CDSFinance/zipline,nborggren/zipline,dhruvparamhans/zipline,zhoulingjun/zipline,otmaneJai/Zipline,mattcaldwell/zipline,StratsOn/zipline,kmather73/zipline,AlirezaShahabi/zipline,umuzungu/zipline,YuepengGuo/zipline,iamkingmaker/zipline,florentchandelier/zipline,erikness/AlephOne,nborggren/zipline,wubr2000/zipline,semio/zipline,grundgruen/zipline,stkubr/zipline,semio/zipline,gwulfs/zipline,StratsOn/zipline,michaeljohnbennett/zipline,alphaBenj/zipline,morrisonwudi/zipline,aajtodd/zipline,Scapogo/zipline,stkubr/zipline,Scapogo/zipline,magne-max/zipline-ja,MonoCloud/zipline,quantopian/zipline,aajtodd/zipline,ChinaQuants/zipline,ronalcc/zipline,joequant/zipline,otmaneJai/Zipline