progrium/buildstep — pull request #58 by nolman (2013-11-14 20:01:26+00:00)
Title: Fixing ruby heroku buildpack

The build pack release step for the heroku-buildpack-ruby is currently broken. It fails to generate a .release file which manifests as the following exception when attempting to YAML load the release file.

/usr/lib/ruby/1.9.1/psych.rb:297:in `initialize': no implicit conversion from nil to integer (TypeError)
from /usr/lib/ruby/1.9.1/psych.rb:297:in `open'
from /usr/lib/ruby/1.9.1/psych.rb:297:in `load_file'

Looking at the [heroku buildpack documentation](https://devcenter.heroku.com/articles/buildpack-api) I believe this is the correct way to invoke release (bin/release $BUILD_DIR)