Add Nix and NixOS as platform engineering tools

[JustAlternate]

Would you guys think the Nix package management and NixOS would be an interesting addition to this awesome list ?

As docker is a way of making repeatable container.
Nix and NixOS can be used for making reproducible systems as code.

[seifrajhi]

Yes, why not it makes sense
You can contribute if you are interested and add them