chore: Add nix flake (#1)

* Add nix flake

* Nix: edit description

.gitignore

@@ -1 +1,7 @@
 _build
+
+# nix ignores
+.direnv
+result
+.envrc
+

flake.nix

@@ -0,0 +1,38 @@
+{
+  description = "A pure OCaml library for manipulating colors in different color spaces";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
+  outputs = inputs@{ flake-parts, ... }:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = [ "x86_64-linux" "aarch64-linux" "aarch64-darwin" "x86_64-darwin" ];
+      perSystem = { config, self', inputs', pkgs, system, ... }:
+        let
+          inherit (pkgs) ocamlPackages mkShell;
+          inherit (ocamlPackages) buildDunePackage;
+          name = "colors";
+          version = "0.0.1";
+        in
+        {
+          devShells = {
+            default = mkShell {
+	      buildInputs = [ ocamlPackages.utop ];
+              inputsFrom = [ self'.packages.default ];
+            };
+          };
+
+          packages = {
+            default = buildDunePackage {
+              inherit version;
+              pname = name;
+	      propagatedBuildInputs = with ocamlPackages; [
+            	(mdx.override {
+              	  inherit logs;
+            	})
+	      ];
+              src = ./.;
+            };
+	  };
+        };
+    };
+}