Documentation: add Grab etcd use case
Documentation: add Grab etcd use case

mkumatag/etcd,sebrandon1/etcd,vimalk78/etcd,bluebreezecf/etcd,mqliang/etcd,lumjjb/etcd,coreos/etcd,bluebreezecf/etcd,whuwxl/etcd,xiang90/etcd,bdarnell/etcd,heyitsanthony/etcd,li-ang/etcd,glevand/coreos--etcd,a-robinson/etcd,joshix/etcd,vimalk78/etcd,armstrongli/etcd,lorneli/etcd,tguangch/etcd,etcd-io/etcd,joshix/etcd,ajityagaty/etcd,glevand/coreos--etcd,fanminshi/etcd,ajityagaty/etcd,yudai/etcd,handsomesun/etcd,visheshnp/etcd,akauppi/etcd,cockroachdb/etcd,lorneli/etcd,rnaveiras/etcd,gyuho/etcd,jlamillan/etcd,dannysauer/etcd,mqliang/etcd,sinsharat/etcd,plasticbox/etcd,xiang90/etcd,YuleiXiao/etcd,visheshnp/etcd,mickep76/etcd,whuwxl/etcd,YuleiXiao/etcd,sebrandon1/etcd,etcd-io/etcd,dannysauer/etcd,rnaveiras/etcd,sinsharat/etcd,bdarnell/etcd,ajityagaty/etcd,yudai/etcd,plasticbox/etcd,mickep76/etcd,heyitsanthony/etcd,rnaveiras/etcd,etcd-io/etcd,armstrongli/etcd,gyuho/etcd,li-ang/etcd,jlamillan/etcd,lumjjb/etcd,mqliang/etcd,coreos/etcd,mkumatag/etcd,cockroachdb/etcd,handsomesun/etcd,akauppi/etcd,tguangch/etcd,a-robinson/etcd,mkumatag/etcd,fanminshi/etcd