activesupport需要Ruby版本＆gt; = 2.2.2。即使我有红宝石2.2.3

Question

为什么我的Ubuntu服务器出现此错误？

rails@myapp:~/www/digitalshelving/current$ rvm use  ruby-2.4.0@5.1
Using /usr/local/rvm/gems/ruby-2.4.0 with gemset 5.1
rails@myapp:~/www/digitalshelving/current$ ruby -v

ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]

rails@myapp:~/www/digitalshelving/current$ sudo gem install rails --version=5.1.5
[sudo] password for rails: 
ERROR:  Error installing rails:
    activesupport requires Ruby version >= 2.2.2.
rails@myapp:~/www/digitalshelving/current$ 

与ruby 2.4.1相同的结果：

rails@myapp:/home$ sudo gem install rails -v 5.1.5
ERROR:  Error installing rails:
    activesupport requires Ruby version >= 2.2.2.
rails@myapp:/home$ ruby -v
ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux]

我找不到任何意义

由于