此命令将查看您的Gemfile并在指定的版本上安装相关的Gems.

安装Gemfiles是因为在你的Gemfile中你指出了可以从中下载gem的源.

您可以通过在shell中键入bundle init来创建Gemfile

我添加了一个Gemfile示例供您参考：

source "https://rubygems.org"  # where gems will be downloaded from
ruby "2.2.3"  # ruby version,change for the one you use

gem "sinatra"
gem "sinatra-flash"
gem "sinatra-partial"
gem "bcrypt"
gem "dm-validations"
gem "dm-transactions"
gem "data_mapper"
gem "dm-postgres-adapter"
gem "pg"
gem "database_cleaner"

group :test do   # you can make groups for test,development,production..
  gem "rspec"
  gem "capybara"
  gem "rspec-sinatra"
  gem "cucumber"
  gem "coveralls",require: false
end