could not install activesupport on centos7

[alexshi]

the centos7u2 failed to run lkp with 2.0 ruby,
#bin/lkp run
/usr/share/rubygems/rubygems/core_ext/kernel_require.rb:55:in require': cannot load such file -- active_support/core_ext/enumerable (LoadError) from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:55:in require'
from /home/kuiliang.as/lkp-tests/lib/array_ext.rb:3:in `<top (required)>'
and gem install activesupport keep failed for ruby version, even I has compiled/install ruby 2.3.8:

$sudo gem install activesupport
Fetching: concurrent-ruby-1.1.5.gem (100%)
Successfully installed concurrent-ruby-1.1.5
Fetching: i18n-1.7.0.gem (100%)

HEADS UP! i18n 1.1 changed fallbacks to exclude default locale.
But that may break your application.

Please check your Rails app for 'config.i18n.fallbacks = true'.
If you're using I18n (>= 1.1.0) and Rails (< 5.2.2), this should be
'config.i18n.fallbacks = [I18n.default_locale]'.
If not, fallbacks will be broken in your app by I18n 1.1.x.

For more info see:
https://github.com/svenfuchs/i18n/releases/tag/v1.1.0

Successfully installed i18n-1.7.0
Fetching: thread_safe-0.3.6.gem (100%)
Successfully installed thread_safe-0.3.6
Fetching: tzinfo-1.2.5.gem (100%)
Successfully installed tzinfo-1.2.5
Fetching: zeitwerk-2.2.1.gem (100%)
ERROR: Error installing activesupport:
zeitwerk requires Ruby version >= 2.4.4.