add flake

flake.nix

@@ -0,0 +1,40 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs =
+    {
+      nixpkgs,
+      flake-utils,
+      rust-overlay,
+      ...
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs { inherit system overlays; };
+      in
+      {
+        devShells = {
+          default = pkgs.mkShell {
+            buildInputs = with pkgs; [
+              pkg-config
+              rust-bin.stable.latest.default
+              rust-analyzer
+              cargo-nextest
+              clang
+              llvmPackages.bintools
+              nodejs
+              pnpm
+              just
+            ];
+          };
+
+        };
+      }
+    );
+}