Add nix flake for dev shell

flake.nix

@@ -0,0 +1,33 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+  outputs =
+    { nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            # generic
+            git
+            git-lfs
+            gnumake
+            gnutar
+
+            # frontend
+            nodejs_20
+
+            # backend
+            go_1_22
+            gofumpt
+            golangci-lint
+          ];
+        };
+      }
+    );
+}