feat: Add a flake

pkgs/shared-assets.nix

@@ -0,0 +1,28 @@
+{
+  lib, stdenv
+, python3 # for makesite.py and pgp-sign.py
+}:
+
+stdenv.mkDerivation {
+  pname = "shared-assets";
+  version = "202205120-01";
+
+  src = ../.;
+
+  propagatedBuildInputs = [ python3 python3.pkgs.markdown ];
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp -v makesite.py pgp-sign.py $out/bin
+    cp -vr assets/ $out/
+  '';
+
+  doCheck = false;
+
+  meta = with lib; {
+    description = "Shared assets for polynom.me web pages";
+    homepage = "https://git.polynom.me/polynom.me/shared-assets";
+    maintainers = [];
+    license = licenses.gpl3;
+  };
+}