Topic: Cannot deploy rails app to heroku, fatal: The remote end hung up unexp

i'm following this guide (  https://devcenter.heroku.com/articles/rails3 ) to deploy a rails app to heroku. It all works well until i iusse this command

git push heroku master

i get this error message afterwards

Permission denied (publickey). fatal: The remote end hung up unexpectedly

i googled the error message but haven't found anything i can make use of. It has something to to with Git and ssh keys.