init: Prove the concept of reproducible builds

flake.nix

@@ -0,0 +1,81 @@
+{
+  description = "Hello World Rust application with neofetch and banner";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.11";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, rust-overlay, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        overlays = [ (import rust-overlay) ];
+        pkgs = import nixpkgs {
+          inherit system overlays;
+        };
+        
+        rustToolchain = pkgs.rust-bin.stable.latest.default.override {
+          extensions = [ "rust-src" ];
+        };
+
+        # Build the Rust application
+        rustApp = pkgs.rustPlatform.buildRustPackage {
+          pname = "hello-world";
+          version = "0.1.0";
+          src = ./.;
+          cargoLock = {
+            lockFile = ./Cargo.lock;
+          };
+          nativeBuildInputs = [ rustToolchain ];
+          buildInputs = [
+            pkgs.xorg.libxcb
+          ];
+        };
+
+        # Create a Docker image with the app and dependencies
+        dockerImage = pkgs.dockerTools.buildLayeredImage {
+          name = "hello-world";
+          tag = "latest";
+          
+          contents = [
+            rustApp
+            pkgs.bashInteractive
+            pkgs.coreutils
+          ];
+          
+          config = {
+            Cmd = [ "${rustApp}/bin/hello-world" ];
+            Env = [
+              "PATH=/bin"
+            ];
+          };
+        };
+        
+      in
+      {
+        packages = {
+          default = rustApp;
+          app = rustApp;
+          docker = dockerImage;
+        };
+
+        devShells.default = pkgs.mkShell {
+          buildInputs = [
+            rustToolchain
+            pkgs.rust-analyzer
+            pkgs.docker
+            pkgs.xorg.libxcb
+          ];
+          
+          shellHook = ''
+            echo "Rust development environment loaded!"
+            echo "Rust version: $(rustc --version)"
+          '';
+        };
+      }
+    );
+}