update train.md
update train.md

zeyuanxy/fast-rcnn,EdisonResearch/fast-rcnn,zeyuanxy/fast-rcnn,EdisonResearch/fast-rcnn,zeyuanxy/fast-rcnn,EdisonResearch/fast-rcnn,zeyuanxy/fast-rcnn,EdisonResearch/fast-rcnn,EdisonResearch/fast-rcnn,zeyuanxy/fast-rcnn