Use container based infrastructure on travis-CI
Use container based infrastructure on travis-CI

rolandgeider/wger,wger-project/wger,wger-project/wger,kjagoo/wger_stark,DeveloperMal/wger,petervanderdoes/wger,wger-project/wger,rolandgeider/wger,DeveloperMal/wger,rolandgeider/wger,petervanderdoes/wger,DeveloperMal/wger,wger-project/wger,petervanderdoes/wger,petervanderdoes/wger,rolandgeider/wger,DeveloperMal/wger,kjagoo/wger_stark,kjagoo/wger_stark,kjagoo/wger_stark