add doc build into ci (#6636)
add doc build into ci (#6636)


jamesliu/mxnet,nicklhy/mxnet,stefanhenneking/mxnet,precedenceguo/mxnet,danithaca/mxnet,reminisce/mxnet,jennyzhang0215/incubator-mxnet,xcgoner/dist-mxnet,apache/incubator-mxnet,larroy/mxnet,saurabh3949/mxnet,Northrend/mxnet,sergeykolychev/mxnet,pluskid/mxnet,hpi-xnor/BMXNet,sxjscience/mxnet,vikingMei/mxnet,hpi-xnor/BMXNet,jermainewang/mxnet,jermainewang/mxnet,ptrendx/mxnet,Northrend/mxnet,TuSimple/mxnet,formath/mxnet,thirdwing/mxnet,LinkHS/incubator-mxnet,apaleyes/mxnet,Northrend/mxnet,yajiedesign/mxnet,vikingMei/mxnet,ForkedReposBak/mxnet,zhreshold/mxnet,gautamkmr/incubator-mxnet,formath/mxnet,hpi-xnor/BMXNet,Prasad9/incubator-mxnet,tlby/mxnet,hotpxl/mxnet,danithaca/mxnet,pluskid/mxnet,crazy-cat/incubator-mxnet,yuruofeifei/mxnet,yuruofeifei/mxnet,jamesliu/mxnet,hesseltuinhof/mxnet,smolix/incubator-mxnet,TuSimple/mxnet,jiajiechen/mxnet,solin319/incubator-mxnet,reminisce/mxnet,LinkHS/incubator-mxnet,danithaca/mxnet,crazy-cat/incubator-mxnet,solin319/incubator-mxnet,vikingMei/mxnet,yuruofeifei/mxnet,lxn2/mxnet,szha/mxnet,ForkedReposBak/mxnet,Prasad9/incubator-mxnet,navrasio/mxnet,hotpxl/mxnet,Mega-DatA-Lab/mxnet,CodingCat/mxnet,mbaijal/incubator-mxnet,coder-james/mxnet,precedenceguo/mxnet,arank/mxnet,madjam/mxnet,eric-haibin-lin/mxnet,jennyzhang0215/incubator-mxnet,ptrendx/mxnet,luoyetx/mxnet,navrasio/mxnet,DickJC123/mxnet,thirdwing/mxnet,apaleyes/mxnet,ZihengJiang/mxnet,weleen/mxnet,crazy-cat/incubator-mxnet,precedenceguo/mxnet,sergeykolychev/mxnet,thirdwing/mxnet,ShownX/incubator-mxnet,formath/mxnet,hotpxl/mxnet,yajiedesign/mxnet,LinkHS/incubator-mxnet,saurabh3949/mxnet,vikingMei/mxnet,arikpoz/mxnet,sxjscience/mxnet,yajiedesign/mxnet,piiswrong/mxnet,ykim362/mxnet,sxjscience/mxnet,madjam/mxnet,EvanzzzZ/mxnet,reminisce/mxnet,ptrendx/mxnet,smolix/incubator-mxnet,nicklhy/mxnet,coder-james/mxnet,solin319/incubator-mxnet,smolix/incubator-mxnet,jennyzhang0215/incubator-mxnet,rahul003/mxnet,Mega-DatA-Lab/mxnet,rahul003/mxnet,navrasio/mxnet,ZihengJiang/mxnet,danithaca/mxnet,stefanhenneking/mxnet,eric-haibin-lin/mxnet,kevinthesun/mxnet,szha/mxnet,rahul003/mxnet,LinkHS/incubator-mxnet,antoan2/incubator-mxnet,precedenceguo/mxnet,madjam/mxnet,sxjscience/mxnet,saurabh3949/mxnet,pluskid/mxnet,arank/mxnet,rahul003/mxnet,hotpxl/mxnet,fullfanta/mxnet,mbaijal/incubator-mxnet,solin319/incubator-mxnet,tornadomeet/mxnet,zhreshold/mxnet,precedenceguo/mxnet,piiswrong/mxnet,EvanzzzZ/mxnet,gautamkmr/incubator-mxnet,navrasio/mxnet,stefanhenneking/mxnet,fullfanta/mxnet,indhub/mxnet,apaleyes/mxnet,Northrend/mxnet,madjam/mxnet,apaleyes/mxnet,Prasad9/incubator-mxnet,Mega-DatA-Lab/mxnet,szha/mxnet,weleen/mxnet,larroy/mxnet,vikingMei/mxnet,leezu/mxnet,smolix/incubator-mxnet,zhreshold/mxnet,nicklhy/mxnet,danithaca/mxnet,apaleyes/mxnet,jennyzhang0215/incubator-mxnet,smolix/incubator-mxnet,precedenceguo/mxnet,indhub/mxnet,vikingMei/mxnet,leezu/mxnet,CodingCat/mxnet,jermainewang/mxnet,Ldpe2G/mxnet,DR08/mxnet,arikpoz/mxnet,EvanzzzZ/mxnet,LinkHS/incubator-mxnet,arikpoz/mxnet,ptrendx/mxnet,hpi-xnor/BMXNet,sxjscience/mxnet,EvanzzzZ/mxnet,weleen/mxnet,pluskid/mxnet,wangyum/mxnet,TuSimple/mxnet,xcgoner/dist-mxnet,eric-haibin-lin/mxnet,Mega-DatA-Lab/mxnet,ForkedReposBak/mxnet,TuSimple/mxnet,tornadomeet/mxnet,hesseltuinhof/mxnet,pluskid/mxnet,tlby/mxnet,tlby/mxnet,Northrend/mxnet,crazy-cat/incubator-mxnet,leezu/mxnet,rahul003/mxnet,navrasio/mxnet,yuruofeifei/mxnet,xcgoner/dist-mxnet,antoan2/incubator-mxnet,larroy/mxnet,jamesliu/mxnet,eric-haibin-lin/mxnet,EvanzzzZ/mxnet,arank/mxnet,pluskid/mxnet,gautamkmr/incubator-mxnet,precedenceguo/mxnet,ykim362/mxnet,hpi-xnor/BMXNet,Prasad9/incubator-mxnet,kkk669/mxnet,LinkHS/incubator-mxnet,hesseltuinhof/mxnet,arank/mxnet,lxn2/mxnet,formath/mxnet,solin319/incubator-mxnet,solin319/incubator-mxnet,reminisce/mxnet,jermainewang/mxnet,ptrendx/mxnet,thirdwing/mxnet,coder-james/mxnet,luoyetx/mxnet,larroy/mxnet,dmlc/mxnet,jiajiechen/mxnet,hesseltuinhof/mxnet,jiajiechen/mxnet,Ldpe2G/mxnet,eric-haibin-lin/mxnet,leezu/mxnet,gautamkmr/incubator-mxnet,dmlc/mxnet,DickJC123/mxnet,hpi-xnor/BMXNet,ShownX/incubator-mxnet,vikingMei/mxnet,jiajiechen/mxnet,arikpoz/mxnet,tlby/mxnet,rahul003/mxnet,larroy/mxnet,LinkHS/incubator-mxnet,jamesliu/mxnet,coder-james/mxnet,vikingMei/mxnet,mbaijal/incubator-mxnet,Ldpe2G/mxnet,thirdwing/mxnet,gautamkmr/incubator-mxnet,lxn2/mxnet,hpi-xnor/BMXNet,piiswrong/mxnet,sergeykolychev/mxnet,TuSimple/mxnet,zhreshold/mxnet,ptrendx/mxnet,Mega-DatA-Lab/mxnet,ZihengJiang/mxnet,ShownX/incubator-mxnet,nicklhy/mxnet,jermainewang/mxnet,thirdwing/mxnet,saurabh3949/mxnet,antoan2/incubator-mxnet,szha/mxnet,crazy-cat/incubator-mxnet,wangyum/mxnet,ykim362/mxnet,ZihengJiang/mxnet,crazy-cat/incubator-mxnet,kkk669/mxnet,hpi-xnor/BMXNet,lxn2/mxnet,CodingCat/mxnet,antoan2/incubator-mxnet,Prasad9/incubator-mxnet,arikpoz/mxnet,antoan2/incubator-mxnet,jamesliu/mxnet,reminisce/mxnet,jiajiechen/mxnet,kkk669/mxnet,jiajiechen/mxnet,yuruofeifei/mxnet,reminisce/mxnet,DR08/mxnet,lxn2/mxnet,CodingCat/mxnet,fullfanta/mxnet,szha/mxnet,stefanhenneking/mxnet,antoan2/incubator-mxnet,indhub/mxnet,kevinthesun/mxnet,tornadomeet/mxnet,fullfanta/mxnet,ykim362/mxnet,Prasad9/incubator-mxnet,mbaijal/incubator-mxnet,ForkedReposBak/mxnet,DickJC123/mxnet,coder-james/mxnet,smolix/incubator-mxnet,mbaijal/incubator-mxnet,kkk669/mxnet,antoan2/incubator-mxnet,jamesliu/mxnet,rahul003/mxnet,Northrend/mxnet,yajiedesign/mxnet,eric-haibin-lin/mxnet,xcgoner/dist-mxnet,DickJC123/mxnet,Ldpe2G/mxnet,reminisce/mxnet,stefanhenneking/mxnet,szha/mxnet,kevinthesun/mxnet,hesseltuinhof/mxnet,jennyzhang0215/incubator-mxnet,Ldpe2G/mxnet,TuSimple/mxnet,CodingCat/mxnet,navrasio/mxnet,reminisce/mxnet,stefanhenneking/mxnet,hesseltuinhof/mxnet,zhreshold/mxnet,yuruofeifei/mxnet,xcgoner/dist-mxnet,yajiedesign/mxnet,szha/mxnet,TuSimple/mxnet,xcgoner/dist-mxnet,apaleyes/mxnet,apaleyes/mxnet,EvanzzzZ/mxnet,hotpxl/mxnet,xcgoner/dist-mxnet,antoan2/incubator-mxnet,dmlc/mxnet,Northrend/mxnet,mbaijal/incubator-mxnet,dmlc/mxnet,Ldpe2G/mxnet,nicklhy/mxnet,piiswrong/mxnet,jennyzhang0215/incubator-mxnet,madjam/mxnet,arank/mxnet,dmlc/mxnet,EvanzzzZ/mxnet,tornadomeet/mxnet,tlby/mxnet,fullfanta/mxnet,ZihengJiang/mxnet,jiajiechen/mxnet,weleen/mxnet,apache/incubator-mxnet,hotpxl/mxnet,CodingCat/mxnet,wangyum/mxnet,dmlc/mxnet,stefanhenneking/mxnet,arank/mxnet,tornadomeet/mxnet,piiswrong/mxnet,szha/mxnet,Mega-DatA-Lab/mxnet,apache/incubator-mxnet,larroy/mxnet,Ldpe2G/mxnet,sergeykolychev/mxnet,formath/mxnet,nicklhy/mxnet,ShownX/incubator-mxnet,danithaca/mxnet,sergeykolychev/mxnet,tlby/mxnet,DR08/mxnet,formath/mxnet,apaleyes/mxnet,wangyum/mxnet,EvanzzzZ/mxnet,wangyum/mxnet,jamesliu/mxnet,navrasio/mxnet,kkk669/mxnet,fullfanta/mxnet,TuSimple/mxnet,dmlc/mxnet,crazy-cat/incubator-mxnet,CodingCat/mxnet,gautamkmr/incubator-mxnet,wangyum/mxnet,hesseltuinhof/mxnet,ZihengJiang/mxnet,madjam/mxnet,solin319/incubator-mxnet,piiswrong/mxnet,sergeykolychev/mxnet,tlby/mxnet,rahul003/mxnet,lxn2/mxnet,ShownX/incubator-mxnet,rahul003/mxnet,lxn2/mxnet,sxjscience/mxnet,tornadomeet/mxnet,DR08/mxnet,hpi-xnor/BMXNet,mbaijal/incubator-mxnet,yajiedesign/mxnet,kkk669/mxnet,ShownX/incubator-mxnet,navrasio/mxnet,solin319/incubator-mxnet,weleen/mxnet,luoyetx/mxnet,fullfanta/mxnet,jennyzhang0215/incubator-mxnet,eric-haibin-lin/mxnet,Ldpe2G/mxnet,zhreshold/mxnet,stefanhenneking/mxnet,sxjscience/mxnet,arank/mxnet,indhub/mxnet,ZihengJiang/mxnet,larroy/mxnet,ForkedReposBak/mxnet,DR08/mxnet,saurabh3949/mxnet,saurabh3949/mxnet,jiajiechen/mxnet,precedenceguo/mxnet,yuruofeifei/mxnet,leezu/mxnet,jamesliu/mxnet,indhub/mxnet,jermainewang/mxnet,coder-james/mxnet,yajiedesign/mxnet,xcgoner/dist-mxnet,wangyum/mxnet,madjam/mxnet,nicklhy/mxnet,yajiedesign/mxnet,weleen/mxnet,crazy-cat/incubator-mxnet,Northrend/mxnet,jermainewang/mxnet,indhub/mxnet,crazy-cat/incubator-mxnet,CodingCat/mxnet,ykim362/mxnet,xcgoner/dist-mxnet,kevinthesun/mxnet,zhreshold/mxnet,precedenceguo/mxnet,ForkedReposBak/mxnet,Mega-DatA-Lab/mxnet,yuruofeifei/mxnet,hotpxl/mxnet,tlby/mxnet,vikingMei/mxnet,jermainewang/mxnet,nicklhy/mxnet,jennyzhang0215/incubator-mxnet,arank/mxnet,solin319/incubator-mxnet,eric-haibin-lin/mxnet,DR08/mxnet,sergeykolychev/mxnet,Mega-DatA-Lab/mxnet,luoyetx/mxnet,arikpoz/mxnet,ptrendx/mxnet,saurabh3949/mxnet,piiswrong/mxnet,zhreshold/mxnet,tornadomeet/mxnet,indhub/mxnet,arank/mxnet,jennyzhang0215/incubator-mxnet,gautamkmr/incubator-mxnet,zhreshold/mxnet,ZihengJiang/mxnet,ZihengJiang/mxnet,eric-haibin-lin/mxnet,leezu/mxnet,leezu/mxnet,smolix/incubator-mxnet,DR08/mxnet,weleen/mxnet,jermainewang/mxnet,Ldpe2G/mxnet,CodingCat/mxnet,kkk669/mxnet,ykim362/mxnet,kevinthesun/mxnet,formath/mxnet,larroy/mxnet,sxjscience/mxnet,yajiedesign/mxnet,danithaca/mxnet,arikpoz/mxnet,pluskid/mxnet,smolix/incubator-mxnet,kevinthesun/mxnet,Prasad9/incubator-mxnet,danithaca/mxnet,luoyetx/mxnet,sxjscience/mxnet,yuruofeifei/mxnet,leezu/mxnet,szha/mxnet,luoyetx/mxnet,kevinthesun/mxnet,mbaijal/incubator-mxnet,reminisce/mxnet,arikpoz/mxnet,ShownX/incubator-mxnet,fullfanta/mxnet,jamesliu/mxnet,pluskid/mxnet,Prasad9/incubator-mxnet,leezu/mxnet,luoyetx/mxnet,ptrendx/mxnet,kkk669/mxnet,ForkedReposBak/mxnet,ptrendx/mxnet,ykim362/mxnet,tornadomeet/mxnet,kevinthesun/mxnet,hotpxl/mxnet,mbaijal/incubator-mxnet,ShownX/incubator-mxnet,kevinthesun/mxnet,TuSimple/mxnet,formath/mxnet,saurabh3949/mxnet,LinkHS/incubator-mxnet,coder-james/mxnet,dmlc/mxnet,gautamkmr/incubator-mxnet,wangyum/mxnet,gautamkmr/incubator-mxnet,dmlc/mxnet,apaleyes/mxnet,hotpxl/mxnet,ptrendx/mxnet,Northrend/mxnet,formath/mxnet,apache/incubator-mxnet,piiswrong/mxnet,jiajiechen/mxnet,ykim362/mxnet,piiswrong/mxnet,larroy/mxnet,luoyetx/mxnet,hesseltuinhof/mxnet,weleen/mxnet,navrasio/mxnet,wangyum/mxnet,weleen/mxnet,ForkedReposBak/mxnet,fullfanta/mxnet,tlby/mxnet,madjam/mxnet,saurabh3949/mxnet,arikpoz/mxnet,kkk669/mxnet,sergeykolychev/mxnet,EvanzzzZ/mxnet,reminisce/mxnet,thirdwing/mxnet,ykim362/mxnet,nicklhy/mxnet,ForkedReposBak/mxnet,thirdwing/mxnet,LinkHS/incubator-mxnet,DR08/mxnet,indhub/mxnet,Prasad9/incubator-mxnet,TuSimple/mxnet,danithaca/mxnet,lxn2/mxnet,hesseltuinhof/mxnet,Mega-DatA-Lab/mxnet,stefanhenneking/mxnet,antoan2/incubator-mxnet,coder-james/mxnet,coder-james/mxnet,madjam/mxnet,indhub/mxnet,thirdwing/mxnet,tlby/mxnet,pluskid/mxnet,DR08/mxnet,lxn2/mxnet,smolix/incubator-mxnet,luoyetx/mxnet,sergeykolychev/mxnet,ShownX/incubator-mxnet,tornadomeet/mxnet