This project rocks and uses MIT-LICENSE.

add this to your gemfile

gem 'seed_data_migrations'

run the following in the command line

bundle install
rake seed_data_migrations_engine:install:migrations
rake db:migrate

This is best shown by a example… (very similar to schema migrations)

rails g seed_data_migrations  description_of_your_data_migration
   =>  create  db/seeds/20140224043148_description_of_your_data_migration.rb
rake db:migrate_data