Ruby on rails Spree:heroku部署错误

我不断得到以下信息：

remote:        Gem::InstallError: spree_core requires Ruby version >= 2.1.0.
remote:        An error occurred while installing spree_core (3.0.4), and Bundler cannot
remote:        continue.
remote:        Make sure that `gem install spree_core -v '3.0.4'` succeeds before bundling.

2.2.2 (set by /Users/Martijn/.rbenv/version)

当我跑的时候

gem install spree_code -v '3.0.4' 

它是成功的，之后当我再次运行git push heroku master时，我得到了完全相同的错误

rbenv versions 

显示如下：

remote:        Gem::InstallError: spree_core requires Ruby version >= 2.1.0.
remote:        An error occurred while installing spree_core (3.0.4), and Bundler cannot
remote:        continue.
remote:        Make sure that `gem install spree_core -v '3.0.4'` succeeds before bundling.

2.2.2 (set by /Users/Martijn/.rbenv/version)

---

Heroku需要Gemfile中定义的ruby版本，如：

---

ruby“2.2.1”

。更多信息：。

请将您的gem文件粘贴到这里？