>创建Gemfile(运行bundle init创建骨架Gemfile)
>捆绑安装
>在您的应用程序中：

# Only needed for ruby 1.8.x
require 'rubygems'

# The part that activates bundler in your app
require 'bundler/setup' 

# require your gems as usual
require 'some_gem'

# ...or require all the gems in one statement
Bundler.require

值得一看：

Bundler.io – Using Bundler in Your Appplication
Bundler.io – Bundler.setup and Bundler.require

Are bundle exec and require ‘bundler/setup’ equivalent?