Added Rake development dependency for Travis-CI
Added Rake development dependency for Travis-CI

tduehr/omniauth-cas3,twowordbird/omniauth-tequila,dlindahl/omniauth-cas,LabSEC/omniauth-cas,gcmalloc/omniauth-tequila,1dtouch/omniauth-cas,identification-io/omniauth-cas,CruGlobal/omniauth-cas,ikbear/omniauth-cas,txstate-etc/omniauth-cas