Why does Rails still need Ruby => 1.9.3 after upgrading to 2.2.6?

Question

I am reinstalling Ruby (latest version 1.9.1) to version 2.2.6. I do this because I tried to install the Rails gem, but when I did gem install rails, I received an error message:

ERROR:  Error installing rails:
    i18n requires Ruby version >= 1.9.3.

So, I installed Ruby again, but now before version 2.2.6 everything went well, but when, again, trying to install Rails-gem, I still get the same error.

When I write ruby -vin the console, it returns:

ruby 2.2.6p396 (2016-11-15 revision 56800) [x86_64-linux]

I really would not want to restart the server for it to take effect, is this the only way?

Thanks everyone!