You could run a Rake task to update the db. The proper way to do this
would be to write a rake task, but the easiest way to get going would
be to use the provided rake task db:seed. This runs the file
db/seeds.rb in the context of the application, so that all the
ActiveRecord stuff is automatically available. To run the rake task
or if you want it to run on the production db
RAILS_ENV=production rake db:seed
which could be run from a cron task or whatever is appropriate.
So all you need do is to put your code in db/seeds.rb and you will be
up and running.