Heroku - Application Error
Try restarting your app with heroku restart
. Assuming your app runs fine locally, this should do the trick. It solved the issue for me as I only refactored the schema and the db:reset did not seem to do the trick.
Most of the time heroku issues are due to lack of privileges to access file system. In order for your application to work on heroku you must make sure it wont try to write anything to disk (but in temporary folder).
The typical example is js/css compiling process, e.g. with compass, for which you will find a solution on their knowledge database: http://devcenter.heroku.com/articles/using-compass
You should look further in the heroku logs see if there is any "permission denied" issue at application startup or during the first requests.
http://www.youtube.com/watch?v=p_3dIPgXgkg
If you already have your application built, go to the point in the video when he begins pushing the sample app to heroku. Unfortunately heroku returns hard to solve errors when uploading 3.1 apps for the first time. Follow the troubleshooting steps in the video and you'll be fine.
Try using the command
heroku run rake db:migrate