No javascript runtime on Heroku

Hello all,

I developed an app using Rails 3.1 and uploaded it to heroku. When I typed rake db:migrate , I got the following error:

Could not find a JavaScript runtime. See for a list of available runtimes.

Does heroku support Rails 3.1? They seem to have no Javascript runtime env's like nodejs on their machine!

Have you read their article on rails 3.1 support ? ( Rails Asset Pipeline on Heroku | Heroku Dev Center )


Thanks a lot Federick