This is short tutorial to step to install Ruby and ruby development kit on windows,
Step 1: Download Ruby Installer from Ruby website. (http://rubyinstaller.org/downloads/)
Step 2: Complete the installation of ruby. Then verify the ruby by running this command
ruby -v. If it shows ruby version, you system is successfully installed with ruby.
Step 3: Now, download the respective DevKit. i.e if you installed Ruby 2.1.6 download the respective devkit from the same website.
Step 4: Extract the downloaded devkit files into any permanent folder.
Step 4: Open cmd and navigate to that devkit folder.
Step 5: Run the following commands,
> dk.rb init
> dk.rb review
> dk.rb install
Step 6: That’s all. You are done.