add doc and example
add doc and example

FCP-INDI/nipype,Leoniela/nipype,dgellis90/nipype,JohnGriffiths/nipype,blakedewey/nipype,pearsonlab/nipype,glatard/nipype,carolFrohlich/nipype,gerddie/nipype,mick-d/nipype_source,blakedewey/nipype,arokem/nipype,carlohamalainen/nipype,glatard/nipype,glatard/nipype,carlohamalainen/nipype,dgellis90/nipype,dmordom/nipype,fprados/nipype,dgellis90/nipype,mick-d/nipype_source,dgellis90/nipype,Leoniela/nipype,carolFrohlich/nipype,FCP-INDI/nipype,fprados/nipype,dmordom/nipype,FCP-INDI/nipype,gerddie/nipype,wanderine/nipype,pearsonlab/nipype,wanderine/nipype,dmordom/nipype,JohnGriffiths/nipype,mick-d/nipype,carlohamalainen/nipype,iglpdc/nipype,rameshvs/nipype,rameshvs/nipype,iglpdc/nipype,rameshvs/nipype,carolFrohlich/nipype,glatard/nipype,gerddie/nipype,pearsonlab/nipype,wanderine/nipype,sgiavasis/nipype,iglpdc/nipype,FCP-INDI/nipype,gerddie/nipype,pearsonlab/nipype,mick-d/nipype_source,sgiavasis/nipype,arokem/nipype,blakedewey/nipype,mick-d/nipype,mick-d/nipype,carolFrohlich/nipype,FredLoney/nipype,JohnGriffiths/nipype,wanderine/nipype,rameshvs/nipype,mick-d/nipype,JohnGriffiths/nipype,FredLoney/nipype,fprados/nipype,sgiavasis/nipype,FredLoney/nipype,sgiavasis/nipype,grlee77/nipype,grlee77/nipype,grlee77/nipype,grlee77/nipype,iglpdc/nipype,arokem/nipype,arokem/nipype,Leoniela/nipype,blakedewey/nipype