How to tell heroku to use rails 3 and ruby 1.9.2 for a newly created app?
If you've already created the application on Heroku it will have defaulted to 1.8.7 as you've found. You can specify the stack to create the application on when you create your app;
heroku create myapp --stack bamboo-mri-1.9.2To migrate your app to 1.9.2 you will need to issue
heroku stack:migrate bamboo-mri-1.9.2Once migrated you will need to repush your application (if i remember correctly)
The problem is not the Ruby or Rails version.
The problem here is that you are trying to use MySQL while Heroku only supports PostgreSQL.
In this page you can find the instructions to migrate to a different Heroku stack.