The Travis CLI user documentation at https://github.com/travis-ci/travis.rb#windows recommends that you use the RubyInstaller (http://rubyinstaller.org/) to install the latest version of Ruby on the Windows OS.
We need to pick Ruby Devkit version 2.5.1 at the RubyInstaller download site and then make sure to accept the license agreement and then choose the appropriate options for the installation. Make sure to install the development toolchain.
When the installer window closes, a Command Prompt will open and you will need to pick an option; you can just hit enter to install all three options on your system. The installation process could take a while to finish. Mine took about 20 minutes to update GPG keys and to install ...
