add StringSliceFlag as possible flag type
add StringSliceFlag as possible flag type

ryanvz/rack,ryanvz/rack,DonNateR/rack,dolph/rack,jrperritt/rack,brint/rack,pratikmallya/rack,DonNateR/rack,pratikmallya/rack,nelsnelson/rack,annegentle/rack,jrperritt/rack,nelsnelson/rack,jarosser06/rack,dolph/rack,annegentle/rack,rackspace/rack,jarosser06/rack,brint/rack,rackspace/rack