Add nix-shell

Author: eonpatapon

shell.nix

@@ -0,0 +1,8 @@
+let
+  pkgs = import <nixpkgs> {};
+in
+  pkgs.mkShell {
+    buildInputs = with pkgs; [
+      (python3.withPackages (ps: with ps; [mpd2 dbus-python pygobject3 mutagen]))
+    ];
+  }