travis: add ruby 2.5.0
travis: add ruby 2.5.0
ramiroaraujo/image_optim,ramiroaraujo/image_optim,mihailim/image_optim,mihailim/image_optim,ramiroaraujo/image_optim,toy/image_optim,toy/image_optim,toy/image_optim,mihailim/image_optim