Elastic Beanstalk,Bundler 找不到 gem "bundler" 的兼容版本

Elastic Beanstalk, Bundler could not find compatible versions for gem "bundler"

我已尝试 rails 的 Elastic Beanstalk。当我 运行 eb deploy 我得到这个错误。我需要至少安装 bundler 1.8.4。知道如何解决这个问题吗?

 Bundler could not find compatible versions for gem "bundler":
    In Gemfile:
      bundler (>= 1.8.4) ruby

  Current Bundler version:
     bundler (1.7.3)

 This Gemfile requires a different version of Bundler.
 Perhaps you need to update Bundler by running `gem install bundler`? (Executor::NonZeroExitStatus)

我正在通过向我的项目添加弹性 beantalk 配置文件来升级预安装的捆绑器。我是 运行 旧版本的 Elastic beanstalk box,所以请随意更改 ruby 路径以适合您的盒子。

文件名:
.ebextensions/upgrade_bundler.config

文件内容:

commands:
  update_bundler:
    command: /opt/rubies/ruby-2.1.5/bin/gem install bundler -v 1.8.4