Why wouldn't it be available? Nix packages are on github. [1]
> And that's on top the fact that "if you tried to follow this article step by step, you’ll have noticed that the versions of ruby and node you installed are probably slightly different from the ones above"
That's the same as on any other host. If I write about installing ruby on ubuntu today and you read the blog post a whole later you'll probably get a newer version.
Why wouldn't it be available? Nix packages are on github. [1]
> And that's on top the fact that "if you tried to follow this article step by step, you’ll have noticed that the versions of ruby and node you installed are probably slightly different from the ones above"
That's the same as on any other host. If I write about installing ruby on ubuntu today and you read the blog post a whole later you'll probably get a newer version.
[1]https://github.com/NixOS/nixpkgs