NixOS configuration

1. git clone repository into ~/.config/nixpkgs
2. cd ~/.config/nixpkgs
3. ln -s the appropriate ./systems/.../configuration.nix to /etc/nixos/configuration.nix
4. rebuild the system sudo nixos-rebuild switch and be happy ;-). In case the system needs a separate nixpkgs, you can use sudo nixos-rebuild -I nixpkgs=/path/to/nixpkgs switch.

For keeping a fork updates, we can add two remotes, upstream and origin. Then we can push everything from one to the other regularly using:

git push origin -f 'refs/remotes/upstream/*:refs/heads/*'