nix-shell environment for middleman

default.nix

# nix-shell -p bundler bundix 
# bundler lock && bundler package --path vendor/cache --no-install && bundix && exit 
# nix-shell
with (import <nixpkgs> {});
let
  env = bundlerEnv {
		name = "test-package";
		inherit ruby;
		gemfile = ./Gemfile;
		lockfile = ./Gemfile.lock;
		gemset = ./gemset.nix;
	};
	in stdenv.mkDerivation {
	  name = "test-package";
		buildInputs = [
		  env
		  ruby
		  zlib # needed by nokogiri
		  libiconv # needed by nokogiri
		  nodejs
		];

	shellHook = ''
      npm install bower
	  ./node_modules/bower/bin/bower install
    '';
	}