build via nix

flake.nix

@@ -2,16 +2,35 @@
   inputs = {
     utils.url = "github:numtide/flake-utils";
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.05";
+    cargo2nix = {
+      url = "github:cargo2nix/cargo2nix/release-0.12";
+      inputs.rust-overlay.follows = "rust-overlay";
+    };
+    rust-overlay.url = "github:oxalica/rust-overlay/stable";
   };
   outputs = {
     self,
     nixpkgs,
     utils,
+    cargo2nix,
+    rust-overlay,
   }:
     utils.lib.eachDefaultSystem (
       system: let
-        pkgs = nixpkgs.legacyPackages.${system};
-      in {
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [cargo2nix.overlays.default];
+        };
+
+        rustPkgs = pkgs.rustBuilder.makePackageSet {
+          rustVersion = "1.86.0";
+          packageFun = import ./Cargo.nix;
+        };
+      in rec {
+        packages = {
+          food-tracker = rustPkgs.workspace.food-tracker {};
+          default = packages.food-tracker;
+        };
         devShell = pkgs.mkShell {
           buildInputs = [
             pkgs.cargo