Add nix flake with dev shell (#2)

👷 add nix flake with dev shell

Co-authored-by: Abdel @ StarkWare <45264458+abdelhamidbakhta@users.noreply.github.com>

README.md

@@ -20,6 +20,8 @@
 
 - [Zig](https://ziglang.org/)
 
+Alternatively, if you have [nix](https://nixos.org/) installed, you can get the full development environment `nix develop`.
+
 ## ⚡ Wanna learn Zig fast?
 
 - [Zig language reference](https://ziglang.org/documentation/master/)

flake.nix

@@ -0,0 +1,38 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    flake-utils = {
+      url = "github:numtide/flake-utils";
+    };
+    zig = {
+      url = "github:mitchellh/zig-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, flake-utils, zig, ... }:
+    let
+      overlays = [ zig.overlays.default ];
+      # Support only systems supported by the zig overlay.
+      systems = builtins.attrNames zig.packages;
+    in
+    flake-utils.lib.eachSystem systems (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system overlays;
+        };
+      in
+      {
+        # format with `nix fmt`
+        formatter = pkgs.nixpkgs-fmt;
+
+        devShell = pkgs.mkShell {
+          # Add native packages needed to build the cairo vm here.
+          # You can find packages at https://search.nixos.org/packages
+          nativeBuildInputs = with pkgs; [
+            zigpkgs.master
+          ];
+        };
+      }
+    );
+}