Add nix expression to build the project

default.nix

@@ -0,0 +1,32 @@
+{ sources ? import ./nix/sources.nix
+, system ? builtins.currentSystem
+}:
+
+let
+  rustOverlay = import "${sources.nixpkgs-mozilla}/rust-overlay.nix";
+  cargo2nixOverlay = import "${sources.cargo2nix}/overlay";
+
+  pkgs = import sources.nixpkgs {
+  # pkgs = import <nixpkgs> {
+    inherit system;
+    overlays = [ cargo2nixOverlay rustOverlay ];
+  };
+
+  rustPkgs = pkgs.rustBuilder.makePackageSet' {
+    rustChannel = "stable";
+    packageFun = import ./Cargo.nix;
+    localPatterns =
+      [
+        ''^(src|tests)(/.*)?''
+        ''[^/]*\.(rs|toml)$''
+        # include other directory from the project repository
+        ''^templates(/.*)?''
+        ''^static(/.*)?''
+        ''^.git.*(/.*)?''
+      ];
+    # packageOverrides
+  };
+in
+  (rustPkgs.workspace.hoc {}).overrideAttrs (drv: {
+      buildInputs = drv.buildInputs or [ ] ++ [ pkgs.git ];
+  })