HEROKU: QUICK GUIDE TO DEPLOYING YOUR RAILS APP
Once you're up with the prerequisites: http://docs.heroku.com/quickstart
If you have some specific gem dependencies create a new file called .gems in the root directory of your app e.g.
mislav-will_paginate --version '>= 2.3.11' --source gems.github.com
authlogic --version '>= 2.1.2' --source gems.github.com
then:
cd myapp
git init
git add .
git commit -m "commit to git"
heroku create
git push heroku master
heroku db:push
(if you don't get a running app after the db:push then you may have a schema discrepancy - like when I did by naughtily deleting columns within mysql itself)
REFS: