Add lib file

lib.nix

@@ -0,0 +1,45 @@
+{ lib, nix2container, pkgs, ... }:
+
+lib.extend (
+	final: prev: {
+		img = {
+			baseImage = final.img.mkImage {
+				name = "base";
+				layers = [
+					(final.img.baseLayer pkgs)
+				];
+			};
+
+			baseLayer = pkgs: with pkgs; {
+				deps = [
+					bashInteractive
+					coreutils
+					dockerTools.binSh
+					dockerTools.caCertificates
+					dockerTools.usrBinEnv
+					findutils
+					gnugrep
+					gnused
+				];
+			};
+
+			foldLayers = let
+				merge = parents: current: let
+					layer = nix2container.buildlayer( current // {
+						layers = parents;
+					});
+				in
+					parents ++ [ layer ];
+			in
+				layers: final.foldl merge [] layers;
+
+			mkImage = {
+				name,
+				layers ? [],
+			}: nix2container.buildImage {
+				inherit name;
+				layers = final.img.foldLayers layers;
+			};
+		};
+	}
+)