I\'ve got a rails application where users have to log in. Therefore in order for the application to be usable, there must be one initial user in the system for the first pe
Consider using the rails console. Good for one-off admin tasks where it's not worth the effort to set up a script or migration.
On your production machine:
script/console production
... then ...
User.create(:name => "Whoever", :password => "whichever")
If you're generating this initial user more than once, then you could also add a script in RAILS_ROOT/script/, and run it from the command line on your production machine, or via a capistrano task.