added a flake

flake.nix

@@ -0,0 +1,26 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+      inputs.flake-utils.follows = "flake-utils";
+    };
+  };
+  outputs = { self, nixpkgs, flake-utils, rust-overlay }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs { inherit system overlays; };
+      in
+      with pkgs;
+      {
+        devShells.default = mkShell {
+          # native = dev dependencies
+          nativeBuildInputs = [ rust-bin.stable.latest.default pkg-config ];
+          buildInputs = [];
+        };
+      }
+    );
+}