To make your first Ruby on Rails application using cPanel, follow these simple steps.

1. Login to cPanel.
2. Click on the icon for "Ruby on Rails" (not Ruby Gems)
3. Check the box for "Load on boot?'
4. Fill in the "App Name" box and name it "test"
5. Application Path will be automagically filled in for you as public_html/test
6. Select "production" for the Environment, which should already be selected as the default.
7. Click "Create"

8. Now you can go to http://yourdomain.com/test/public/

You should now see a "Welcome aboard" message which is the default Ruby index page.

If you get a 400 Error, make sure to include the trailing slash "/" after "public" or you may not see the default Rails welcome page.

Example:
http://domain.com/test/public <-- BAD
http://domain.com/test/public/ <-- GOOD

Congratulations, you have setup the basic framework for your new RoR application using cPanel