Do you already know how to develop using ROR? If not then start by
working right through a good tutorial such as railstutorial.org (which
is free to use online) which will show you the basics of Rails.
Once you have done that (or if you already know how to develop with
rails) then in Gemfile remove any database specific gems you have and
replace with
gem 'mysql2'
and in database.yml put
adapter: mysql2
socket: /var/run/mysqld/mysqld.sock