Cache bundler on travis-ci.
Cache bundler on travis-ci.

fulcrum-agile/fulcrum,DrTom/fulcrum,jimbeaudoin/agile-tracker,KentFujii/fulcrum,KentFujii/fulcrum,nh-platform/demo-fulcrum,DrTom/fulcrum,jimbeaudoin/agile-tracker,nh-platform/demo-fulcrum,ipmobiletech/fulcrum,ipmobiletech/fulcrum,DrTom/fulcrum,HenryYan2012/fulcrum,privatt/privatt-agile-tracker,PedroFelipe/cm42-central,fulcrum-agile/fulcrum,privatt/privatt-agile-tracker,KentFujii/fulcrum,fulcrum-agile/fulcrum,Aupajo/fulcrum,HenryYan2012/fulcrum,HenryYan2012/fulcrum,nh-platform/demo-fulcrum,ipmobiletech/fulcrum,Codeminer42/cm42-central,PedroFelipe/cm42-central,privatt/privatt-agile-tracker,Codeminer42/cm42-central,Codeminer42/cm42-central,Aupajo/fulcrum,jimbeaudoin/agile-tracker,Aupajo/fulcrum,PedroFelipe/cm42-central