nix shell script that provides the env needed to "rails new" a project

rails.nix

# https://ghedam.at/15978/an-introduction-to-nix-shell
with (import <nixpkgs> {});
mkShell {
  buildInputs = [
    gcc
    gnumake
    libiconv
    libxml2
    libxslt
    nodejs
    openssl
    pkgconfig
    postgresql
    readline
    ruby
    yarn
    zlib
  ];
  shellHook = ''
    gem_home=$(mktemp -d)
    echo "Using temporary folder for gems... $gem_home"

    export GEM_HOME=$gem_home
    export GEM_PATH=$GEM_HOME
    export PATH=$GEM_HOME/bin:$PATH
    export name="rails-bootstrap: $gem_home"

    gem list -i ^bundler$ || gem install bundler --no-document
    gem list -i ^rails$ || gem install rails --no-document
  '';
}