Running ruby 1.9.3 on Heroku

I had a few problems trying to get ruby 1.9.3 running on Heroku.

Here's the error I had:

 Heroku receiving push
-----> Removing .DS_Store files
-----> Ruby/Sinatra app detected
-----> Gemfile detected, running Bundler version 1.0.7
       Unresolved dependencies detected; Installing...
       Using --without development:test
       /tmp/build_jpq0amd2bp92/Gemfile:5:in `evaluate': undefined method `ruby' for # (NoMethodError)

Here's what I did to fix it:

     Add the following to Gemfile: 
        ruby '1.9.3'
        gem 'bundler', '1.2.0.pre'

git remote rm heroku
heroku create --stack cedar
gem install bundler --pre
bundle install
git commit -am "fixed heroku problem"
git push heroku master

And some notes to myself for other stuff I need:

heroku addons:add mongohq:free
heroku config:add TWITTER_KEY=`echo $TWITTER_KEY`
heroku config:add TWITTER_SECRET_KEY=`echo $TWITTER_SECRET_KEY`