Getting an autotest for working with a cucumber

I'm trying to set up an autotest to work with a cucumber, but despite the following lessons, it always ends:

0 tests, 0 assertions, 0 failures, 0 errors

From this blog post, I see that I need to add something: http://monket.net/blog/2009/06/simple-example-of-autotest-cucumber-and-growl/

AUTOFEATURE=true

I was not sure where to add this, so I tried the config / environment.rb file as well as the /config/environments/development.rb and test.rb file, but that didn't matter.

Does anyone know how I can get an autotest to run cucumber tests? Now I do not have rspec tests, I start with a cucumber.

thank