add doc for dataset (#7644)
add doc for dataset (#7644)


smolix/incubator-mxnet,yuruofeifei/mxnet,solin319/incubator-mxnet,hpi-xnor/BMXNet,szha/mxnet,ForkedReposBak/mxnet,zhreshold/mxnet,Mega-DatA-Lab/mxnet,saurabh3949/mxnet,mbaijal/incubator-mxnet,reminisce/mxnet,ptrendx/mxnet,hpi-xnor/BMXNet,Northrend/mxnet,Prasad9/incubator-mxnet,reminisce/mxnet,piiswrong/mxnet,reminisce/mxnet,jamesliu/mxnet,tornadomeet/mxnet,piiswrong/mxnet,fullfanta/mxnet,tornadomeet/mxnet,solin319/incubator-mxnet,leezu/mxnet,mbaijal/incubator-mxnet,smolix/incubator-mxnet,wangyum/mxnet,tornadomeet/mxnet,larroy/mxnet,ShownX/incubator-mxnet,LinkHS/incubator-mxnet,solin319/incubator-mxnet,vikingMei/mxnet,LinkHS/incubator-mxnet,kkk669/mxnet,crazy-cat/incubator-mxnet,jiajiechen/mxnet,eric-haibin-lin/mxnet,ykim362/mxnet,formath/mxnet,vikingMei/mxnet,jamesliu/mxnet,jennyzhang0215/incubator-mxnet,wangyum/mxnet,szha/mxnet,ShownX/incubator-mxnet,formath/mxnet,saurabh3949/mxnet,DickJC123/mxnet,Mega-DatA-Lab/mxnet,crazy-cat/incubator-mxnet,formath/mxnet,sxjscience/mxnet,eric-haibin-lin/mxnet,kevinthesun/mxnet,eric-haibin-lin/mxnet,antoan2/incubator-mxnet,ptrendx/mxnet,reminisce/mxnet,yajiedesign/mxnet,jennyzhang0215/incubator-mxnet,Mega-DatA-Lab/mxnet,Northrend/mxnet,piiswrong/mxnet,kevinthesun/mxnet,zhreshold/mxnet,jermainewang/mxnet,sxjscience/mxnet,eric-haibin-lin/mxnet,CodingCat/mxnet,TuSimple/mxnet,crazy-cat/incubator-mxnet,smolix/incubator-mxnet,smolix/incubator-mxnet,yajiedesign/mxnet,madjam/mxnet,vikingMei/mxnet,kkk669/mxnet,leezu/mxnet,ShownX/incubator-mxnet,sergeykolychev/mxnet,CodingCat/mxnet,luoyetx/mxnet,weleen/mxnet,luoyetx/mxnet,jiajiechen/mxnet,navrasio/mxnet,eric-haibin-lin/mxnet,rahul003/mxnet,saurabh3949/mxnet,weleen/mxnet,yajiedesign/mxnet,rahul003/mxnet,ptrendx/mxnet,jamesliu/mxnet,ykim362/mxnet,indhub/mxnet,tornadomeet/mxnet,Prasad9/incubator-mxnet,gautamkmr/incubator-mxnet,antoan2/incubator-mxnet,luoyetx/mxnet,larroy/mxnet,formath/mxnet,jennyzhang0215/incubator-mxnet,smolix/incubator-mxnet,crazy-cat/incubator-mxnet,leezu/mxnet,TuSimple/mxnet,rahul003/mxnet,wangyum/mxnet,piiswrong/mxnet,LinkHS/incubator-mxnet,precedenceguo/mxnet,yuruofeifei/mxnet,vikingMei/mxnet,gautamkmr/incubator-mxnet,yajiedesign/mxnet,navrasio/mxnet,hpi-xnor/BMXNet,ykim362/mxnet,leezu/mxnet,ZihengJiang/mxnet,sxjscience/mxnet,CodingCat/mxnet,navrasio/mxnet,yuruofeifei/mxnet,Northrend/mxnet,kkk669/mxnet,jiajiechen/mxnet,kkk669/mxnet,saurabh3949/mxnet,larroy/mxnet,precedenceguo/mxnet,gautamkmr/incubator-mxnet,sergeykolychev/mxnet,ykim362/mxnet,yajiedesign/mxnet,jennyzhang0215/incubator-mxnet,LinkHS/incubator-mxnet,sergeykolychev/mxnet,antoan2/incubator-mxnet,weleen/mxnet,weleen/mxnet,crazy-cat/incubator-mxnet,solin319/incubator-mxnet,TuSimple/mxnet,vikingMei/mxnet,formath/mxnet,navrasio/mxnet,wangyum/mxnet,fullfanta/mxnet,sxjscience/mxnet,Mega-DatA-Lab/mxnet,leezu/mxnet,DickJC123/mxnet,jennyzhang0215/incubator-mxnet,madjam/mxnet,fullfanta/mxnet,larroy/mxnet,yajiedesign/mxnet,navrasio/mxnet,rahul003/mxnet,Prasad9/incubator-mxnet,LinkHS/incubator-mxnet,gautamkmr/incubator-mxnet,sxjscience/mxnet,kevinthesun/mxnet,ForkedReposBak/mxnet,ZihengJiang/mxnet,kkk669/mxnet,DickJC123/mxnet,CodingCat/mxnet,eric-haibin-lin/mxnet,jermainewang/mxnet,mbaijal/incubator-mxnet,antoan2/incubator-mxnet,precedenceguo/mxnet,CodingCat/mxnet,rahul003/mxnet,TuSimple/mxnet,apache/incubator-mxnet,reminisce/mxnet,madjam/mxnet,eric-haibin-lin/mxnet,jamesliu/mxnet,ZihengJiang/mxnet,Northrend/mxnet,piiswrong/mxnet,jennyzhang0215/incubator-mxnet,madjam/mxnet,LinkHS/incubator-mxnet,Northrend/mxnet,Northrend/mxnet,madjam/mxnet,LinkHS/incubator-mxnet,jennyzhang0215/incubator-mxnet,ForkedReposBak/mxnet,Mega-DatA-Lab/mxnet,hpi-xnor/BMXNet,ShownX/incubator-mxnet,smolix/incubator-mxnet,tlby/mxnet,Prasad9/incubator-mxnet,smolix/incubator-mxnet,navrasio/mxnet,ZihengJiang/mxnet,ShownX/incubator-mxnet,tornadomeet/mxnet,sxjscience/mxnet,tornadomeet/mxnet,sergeykolychev/mxnet,wangyum/mxnet,ptrendx/mxnet,madjam/mxnet,kkk669/mxnet,weleen/mxnet,sxjscience/mxnet,ForkedReposBak/mxnet,vikingMei/mxnet,dmlc/mxnet,fullfanta/mxnet,piiswrong/mxnet,formath/mxnet,mbaijal/incubator-mxnet,szha/mxnet,jiajiechen/mxnet,Northrend/mxnet,jennyzhang0215/incubator-mxnet,eric-haibin-lin/mxnet,yajiedesign/mxnet,tlby/mxnet,formath/mxnet,formath/mxnet,kevinthesun/mxnet,gautamkmr/incubator-mxnet,ykim362/mxnet,saurabh3949/mxnet,hpi-xnor/BMXNet,luoyetx/mxnet,ForkedReposBak/mxnet,yuruofeifei/mxnet,Mega-DatA-Lab/mxnet,dmlc/mxnet,tornadomeet/mxnet,kkk669/mxnet,saurabh3949/mxnet,sergeykolychev/mxnet,jamesliu/mxnet,crazy-cat/incubator-mxnet,indhub/mxnet,madjam/mxnet,sergeykolychev/mxnet,jermainewang/mxnet,ShownX/incubator-mxnet,TuSimple/mxnet,larroy/mxnet,jermainewang/mxnet,tlby/mxnet,mbaijal/incubator-mxnet,ForkedReposBak/mxnet,zhreshold/mxnet,antoan2/incubator-mxnet,ZihengJiang/mxnet,smolix/incubator-mxnet,vikingMei/mxnet,saurabh3949/mxnet,szha/mxnet,jermainewang/mxnet,yuruofeifei/mxnet,wangyum/mxnet,dmlc/mxnet,wangyum/mxnet,piiswrong/mxnet,mbaijal/incubator-mxnet,szha/mxnet,dmlc/mxnet,fullfanta/mxnet,hpi-xnor/BMXNet,indhub/mxnet,antoan2/incubator-mxnet,kevinthesun/mxnet,crazy-cat/incubator-mxnet,yajiedesign/mxnet,indhub/mxnet,dmlc/mxnet,tlby/mxnet,solin319/incubator-mxnet,smolix/incubator-mxnet,ForkedReposBak/mxnet,yuruofeifei/mxnet,luoyetx/mxnet,fullfanta/mxnet,ZihengJiang/mxnet,weleen/mxnet,solin319/incubator-mxnet,tornadomeet/mxnet,larroy/mxnet,gautamkmr/incubator-mxnet,precedenceguo/mxnet,jiajiechen/mxnet,jermainewang/mxnet,luoyetx/mxnet,szha/mxnet,szha/mxnet,weleen/mxnet,ShownX/incubator-mxnet,larroy/mxnet,sergeykolychev/mxnet,gautamkmr/incubator-mxnet,Northrend/mxnet,Prasad9/incubator-mxnet,reminisce/mxnet,sxjscience/mxnet,Prasad9/incubator-mxnet,apache/incubator-mxnet,DickJC123/mxnet,kevinthesun/mxnet,sxjscience/mxnet,rahul003/mxnet,tlby/mxnet,jamesliu/mxnet,luoyetx/mxnet,jamesliu/mxnet,ptrendx/mxnet,zhreshold/mxnet,eric-haibin-lin/mxnet,dmlc/mxnet,kevinthesun/mxnet,yuruofeifei/mxnet,piiswrong/mxnet,mbaijal/incubator-mxnet,sergeykolychev/mxnet,zhreshold/mxnet,luoyetx/mxnet,CodingCat/mxnet,tlby/mxnet,crazy-cat/incubator-mxnet,Northrend/mxnet,hpi-xnor/BMXNet,larroy/mxnet,antoan2/incubator-mxnet,saurabh3949/mxnet,precedenceguo/mxnet,reminisce/mxnet,jiajiechen/mxnet,Prasad9/incubator-mxnet,ForkedReposBak/mxnet,precedenceguo/mxnet,LinkHS/incubator-mxnet,apache/incubator-mxnet,rahul003/mxnet,TuSimple/mxnet,apache/incubator-mxnet,ptrendx/mxnet,leezu/mxnet,antoan2/incubator-mxnet,Prasad9/incubator-mxnet,larroy/mxnet,tlby/mxnet,szha/mxnet,ForkedReposBak/mxnet,indhub/mxnet,weleen/mxnet,jennyzhang0215/incubator-mxnet,ZihengJiang/mxnet,jermainewang/mxnet,ZihengJiang/mxnet,ShownX/incubator-mxnet,ykim362/mxnet,madjam/mxnet,ShownX/incubator-mxnet,wangyum/mxnet,formath/mxnet,solin319/incubator-mxnet,Mega-DatA-Lab/mxnet,rahul003/mxnet,solin319/incubator-mxnet,fullfanta/mxnet,antoan2/incubator-mxnet,rahul003/mxnet,ykim362/mxnet,mbaijal/incubator-mxnet,reminisce/mxnet,zhreshold/mxnet,kevinthesun/mxnet,wangyum/mxnet,leezu/mxnet,ptrendx/mxnet,jermainewang/mxnet,fullfanta/mxnet,indhub/mxnet,szha/mxnet,vikingMei/mxnet,navrasio/mxnet,navrasio/mxnet,TuSimple/mxnet,dmlc/mxnet,jamesliu/mxnet,jiajiechen/mxnet,tlby/mxnet,zhreshold/mxnet,yajiedesign/mxnet,vikingMei/mxnet,solin319/incubator-mxnet,CodingCat/mxnet,sergeykolychev/mxnet,navrasio/mxnet,jermainewang/mxnet,fullfanta/mxnet,hpi-xnor/BMXNet,yuruofeifei/mxnet,ykim362/mxnet,ptrendx/mxnet,dmlc/mxnet,precedenceguo/mxnet,zhreshold/mxnet,indhub/mxnet,madjam/mxnet,precedenceguo/mxnet,TuSimple/mxnet,kkk669/mxnet,mbaijal/incubator-mxnet,LinkHS/incubator-mxnet,TuSimple/mxnet,jiajiechen/mxnet,weleen/mxnet,hpi-xnor/BMXNet,crazy-cat/incubator-mxnet,luoyetx/mxnet,ZihengJiang/mxnet,gautamkmr/incubator-mxnet,Prasad9/incubator-mxnet,indhub/mxnet,jamesliu/mxnet,indhub/mxnet,jiajiechen/mxnet,tlby/mxnet,zhreshold/mxnet,saurabh3949/mxnet,reminisce/mxnet,leezu/mxnet,reminisce/mxnet,CodingCat/mxnet,tlby/mxnet,dmlc/mxnet,TuSimple/mxnet,tornadomeet/mxnet,piiswrong/mxnet,ptrendx/mxnet,gautamkmr/incubator-mxnet,Mega-DatA-Lab/mxnet,kevinthesun/mxnet,leezu/mxnet,precedenceguo/mxnet,ykim362/mxnet,ptrendx/mxnet,yuruofeifei/mxnet,CodingCat/mxnet,kkk669/mxnet,Mega-DatA-Lab/mxnet