There are many different provisioning tools out there, the most popular of which are Chef and Puppet. Chef uses Ruby, Puppet uses a DSL (Domain Specific Language), there are others that use simple bash too, but today we're going to focus on Chef Solo.
To get Chef working properly on your local machine you need a few things.
Make sure you use Ruby 1.9.x and not Ruby 2.x as you will get errors with the json 1.6.1 gem on 2.x. Use rbenv or RVM to manage several different Rubies on the one machine.