Adds Gemfile with github-pages gem.
Adds Gemfile with github-pages gem.

nautsio/nautsio.github.io,cargonauts/cargonauts.github.io,cargonauts/cargonauts.github.io,arminc/cargonauts.github.io,nautsio/staging,arminc/cargonauts.github.io,nautsio/staging,ffung/cargonauts.github.io,cargonauts/cargonauts.github.io,ffung/cargonauts.github.io,nautsio/staging,arminc/cargonauts.github.io,nautsio/nautsio.github.io,ffung/cargonauts.github.io