Deployment stacks have been a huge success. With the latest version of Rails 3 requiring the Bamboo stack, we’re excited to make Bamboo the new default.
Effective immediately, all newly created apps will default to the bamboo stack with REE 1.8.7. You can still use the old aspen stack if you’d like by simply specifying `heroku create —stack aspen`. Existing apps stay on the stack they are on unless you explicitly migrate them.
A key feature of bamboo is to eliminate pre-installed gems. This provides app developers with considerably more flexibility in managing their apps. You can easily use any version of any gem by simply including it in your .gems file or Bundler Gemfile. You’ll need to remember to include all gems you are using. If you’re using Gemfile, this is automatically done for you. If you’re using .gems, please make sure to include all the gems you use, INCLUDING rails!