Add flake

flake.nix

@@ -0,0 +1,28 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+  outputs = { self, nixpkgs, ... }: let
+    forAllSystems = f: (nixpkgs.lib.genAttrs [ "x86_64-linux" "aarch64-linux" ] (system: let
+      pkgs = import nixpkgs { inherit system; };
+    in f { inherit pkgs system; } ));
+  in {
+    packages = forAllSystems ({ pkgs, system, ... }: {
+      flake-tracker = pkgs.rustPlatform.buildRustPackage rec {
+        pname = "flake-tracker";
+        version = "0.1.0";
+
+        src = ./.;
+
+        cargoLock.lockFile = ./Cargo.lock;
+
+      };
+      default = self.packages."${system}".flake-tracker;
+    });
+
+    hydraJobs = {
+      inherit (self)
+        packages;
+    };
+  };
+}