add webhook URL to .travis.yml
add webhook URL to .travis.yml

Reviewed By: leebyron

Differential Revision: D5559780

fbshipit-source-id: 767ea00f5b36677020cb89663d51c447b8ecd9c1

voideanvalue/relay,wincent/relay,xuorig/relay,zpao/relay,benjaminogles/relay,facebook/relay,benjaminogles/relay,freiksenet/relay,yungsters/relay,xuorig/relay,facebook/relay,freiksenet/relay,xuorig/relay,freiksenet/relay,josephsavona/relay,iamchenxin/relay,zpao/relay,voideanvalue/relay,wincent/relay,xuorig/relay,yungsters/relay,cpojer/relay,kassens/relay,iamchenxin/relay,iamchenxin/relay,josephsavona/relay,yungsters/relay,rosskevin/relay,voideanvalue/relay,dbslone/relay,atxwebs/relay,josephsavona/relay,wincent/relay,zpao/relay,xuorig/relay,cpojer/relay,voideanvalue/relay,wincent/relay,kassens/relay,atxwebs/relay,voideanvalue/relay,atxwebs/relay,facebook/relay,facebook/relay,xuorig/relay,cpojer/relay,kassens/relay,apalm/relay,kassens/relay,voideanvalue/relay,rosskevin/relay,cpojer/relay,dbslone/relay,facebook/relay,atxwebs/relay,iamchenxin/relay,wincent/relay,kassens/relay,facebook/relay,benjaminogles/relay,apalm/relay,kassens/relay,apalm/relay,wincent/relay