message: Add gentoo instructions.
diff: @@ -162,6 +162,22 @@ The following command can be used to get a shell with all development dependenci
  nix-shell -A alacritty '<nixpkgs>'
  ```
  +#### Gentoo
  +
  +On Gentoo, there's a portage overlay available. Make sure `layman` is installed
  +and run:
  +```
  +sudo layman -a slyfox
  +```
  +Then, add `x11-terms/alacritty **` to `/etc/portage/package.accept_keywords`
  +and emerge alacritty:
  +```
  +sudo emerge alacritty
  +```
  +It might be handy to mask all other packages provided in the `slyfox` overlay by
  +adding `*/*::slyfox` to `/etc/portage/package.mask` and adding
  +`x11-terms/alacritty::slyfox` to `/etc/portage/package.unmask`.
  +
  #### Other
  If you build Alacritty on another distribution, we would love some help
  