How to update ruby in windows
I recommend using Chocolatey to manage your ruby installation.
It's a unix style package manager for windows.
It's quite easy to install, you can find instructions on their website.
In cmd.exe (run as administrator):
@powershell -NoProfile -ExecutionPolicy Bypass -Command "iex ((new-object net.webclient).DownloadString('https://chocolatey.org/install.ps1'))" && SET PATH=%PATH%;%ALLUSERSPROFILE%\chocolatey\bin
Then you can install ruby:
choco install ruby
And upgrade it later:
choco upgrade ruby
The easiest way for you might be to use RubyInstaller, which its version 2.0.0-p0 is now available for download as installers. Follow the link http://rubyinstaller.org/ for more information.