Update CONTRIBUTING.md
Update CONTRIBUTING.md

Former-commit-id: b86bf86a74e8d86ac56c1f40e02f34277990d17b
wangziqi2016/peloton,vittvolt/peloton,AngLi-Leon/peloton,eric-haibin-lin/peloton-1,malin1993ml/peloton,wangziqi2016/peloton,PauloAmora/peloton,PauloAmora/peloton,vittvolt/15721-peloton,malin1993ml/peloton,AllisonWang/peloton,seojungmin/peloton,yingjunwu/peloton,vittvolt/peloton,ShuxinLin/peloton,phisiart/peloton-p3,yingjunwu/peloton,cmu-db/peloton,PauloAmora/peloton,apavlo/peloton,seojungmin/peloton,malin1993ml/peloton,haojin2/peloton,eric-haibin-lin/peloton-1,ShuxinLin/peloton,malin1993ml/peloton,AngLi-Leon/peloton,prashasthip/peloton,yingjunwu/peloton,cmu-db/peloton,seojungmin/peloton,yingjunwu/peloton,apavlo/peloton,cmu-db/peloton,AllisonWang/peloton,AngLi-Leon/peloton,AllisonWang/peloton,vittvolt/15721-peloton,haojin2/peloton,malin1993ml/peloton,PauloAmora/peloton,haojin2/peloton,ShuxinLin/peloton,cmu-db/peloton,eric-haibin-lin/peloton-1,seojungmin/peloton,seojungmin/peloton,vittvolt/15721-peloton,PauloAmora/peloton,prashasthip/peloton,vittvolt/peloton,jessesleeping/iso_peloton,eric-haibin-lin/peloton-1,eric-haibin-lin/peloton-1,cmu-db/peloton,haojin2/peloton,vittvolt/peloton,seojungmin/peloton,wangziqi2016/peloton,prashasthip/peloton,yingjunwu/peloton,yingjunwu/peloton,malin1993ml/peloton,vittvolt/peloton,PauloAmora/peloton,phisiart/peloton-p3,vittvolt/15721-peloton,vittvolt/15721-peloton,phisiart/peloton-p3,phisiart/peloton-p3,haojin2/peloton,jessesleeping/iso_peloton,prashasthip/peloton,apavlo/peloton,jessesleeping/iso_peloton,ShuxinLin/peloton,vittvolt/15721-peloton,apavlo/peloton,AngLi-Leon/peloton,jessesleeping/iso_peloton,vittvolt/peloton,jessesleeping/iso_peloton,ShuxinLin/peloton,phisiart/peloton-p3,AngLi-Leon/peloton,wangziqi2016/peloton,ShuxinLin/peloton,AllisonWang/peloton,prashasthip/peloton,wangziqi2016/peloton,jessesleeping/iso_peloton,eric-haibin-lin/peloton-1,wangziqi2016/peloton,jessesleeping/iso_peloton,AngLi-Leon/peloton,apavlo/peloton,phisiart/peloton-p3,cmu-db/peloton,AllisonWang/peloton,haojin2/peloton,AllisonWang/peloton,prashasthip/peloton,apavlo/peloton