Symlink 2.3.0 to 2.4.0, 2.5.0, and 2.6.0. When using Ruby 2.4 or newer, fix the error: /usr/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- active_support/core_ext/object/blank (LoadError)
