use facts as suggested in https://github.com/garethr/garethr-docker/pull/557#issuecomment-270368341
use facts as suggested in https://github.com/garethr/garethr-docker/pull/557#issuecomment-270368341

snahelou/garethr-docker,Tradeshift/garethr-docker,bmcbm/garethr-docker,HackerHappyHour/hackerhappyhour-docker,bmcbm/garethr-docker,garethr/garethr-docker,bmcbm/garethr-docker,snahelou/garethr-docker,Tradeshift/garethr-docker,Tradeshift/garethr-docker,garethr/garethr-docker,snahelou/garethr-docker,HackerHappyHour/hackerhappyhour-docker,SUNET/garethr-docker,SUNET/garethr-docker,SUNET/garethr-docker,HackerHappyHour/hackerhappyhour-docker,garethr/garethr-docker