Add flake file

[jkarni]

Issue reference:
#93

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[kvanbere]

I don’t know enough about nix to know whether this is okay or not, but one thing that stands out to me is the flake description - maybe it should be changed from the default.

Happy to merge it.

[kvanbere]

@ashercuedo

[ashercuedo]

Thanks for the pull request, I'll get onto it as soon as I can 👍

[jkarni]

one thing that stands out to me is the flake description - maybe it should be changed from the default.

Good call - changed to something more specific.

[ashercuedo]

Looking pretty good I reckon. Just curious, I'm not super familiar with .Nix - but is there a reason why the file uses nixpkgs from the unstable branch?

nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";

Totally cool if that is a common thing to do, just thinking that since this is supposed to be a generic Flake file we might want to change it to the same as the Nix wiki:

nixpkgs.url = "github:NixOS/nixpkgs";