• Become root.

peregrine ~ # su -

• Install eselect-repository.

peregrine ~ # emerge --ask eselect-repository

• Add the repository.

peregrine ~ # eselect repository add adrenlinerush git https://github.com/adrenlinerush/ebuilds.git

• Sync the repos.

peregrine ~ # emerge --sync

Or

peregrine ~ # eix-sync