Add Nix package derivation

nix/default.nix

@@ -0,0 +1,28 @@
+{ config, fetchgit, pkgs, lib, stdenv, ... }:
+
+stdenv.mkDerivation rec {
+  pname = "lalafin";
+  version = "0.2.0";
+
+  src = [
+    ../target
+  ];
+
+  nativeBuildInputs = [
+    pkgs.makeWrapper
+  ];
+
+  installPhase = ''
+    mkdir -p $out/bin
+    mv *-runner $out/bin/lalafin
+  '';
+
+  postFixup = ''
+    wrapProgram $out/bin/lalafin --prefix PATH : ${pkgs.imagemagick}/bin
+  '';
+
+  meta = with lib; {
+    description = "Overly complex file server";
+    homepage = "https://git.rhiobet.sh/rhiobet/lalafin";
+  };
+}