bowerやrails-assetsの代替としてjsdelivrを使う ref: http://qiita.com/inuscript/items/f709283b377f3c349a62

file0.txt

https://cdn.jsdelivr.net/g/jquery@1.11.3,jquery.ui@1.11.4

file1.txt

https://cdn.jsdelivr.net/g/パッケージ名(@version),パッケージ名...

file2.rb

def generate_jsdelivr_url(pkgs)
    path = pkgs.map{ |pkg_name, v| "#{pkg_name}@#{v}" }.join(",")
    "https://cdn.jsdelivr.net/g/#{path}"
end

pkgs = {
    "jquery": "1.11.3",
    "jquery.ui": "1.11.4"
}

generate_jsdelivr_url(pkgs)
// => "https://cdn.jsdelivr.net/g/jquery@1.11.3,jquery.ui@1.11.4"