add nix flake

flake.nix

@@ -1,24 +1,33 @@
 {
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    flake-parts.inputs.nixpkgs-lib.follows = "nixpkgs";
   };
 
   outputs =
-    { nixpkgs, ... }:
-    {
-      devShells =
-        let
-          system = "x86_64-linux";
-          pkgs = import nixpkgs { inherit system; };
-        in
-        {
-          ${system}.default = pkgs.mkShellNoCC {
-            packages = with pkgs; [
-              deno
-              pkgs.nil # Nix language server
-              pkgs.nixfmt-rfc-style
-            ];
+    inputs@{ flake-parts, ... }:
+    flake-parts.lib.mkFlake
+      {
+        inherit inputs;
+      }
+      {
+        systems = [
+          "x86_64-linux"
+          "aarch64-linux"
+        ];
+
+        perSystem =
+          { pkgs, ... }:
+          {
+            devShells.default = pkgs.mkShellNoCC {
+              packages = [
+                pkgs.deno
+                pkgs.nil # Nix language server
+                pkgs.nixfmt-rfc-style
+              ];
+            };
           };
-        };
-    };
+      };
 }