How to set Thin as default in Rails 3

I've been starting Thin with thin -V start in development.

However, I would like Thin to be the default instead of WEBrick and to be able to start it with rails s.

Is there a way to set Thin as the default instead of WEBrick in Rails 3?

If that's not possible, is there at least a way to start it in the test environment automatically?