* update lib/etl/version
* push your changes
* then use bundler to build + git tag + push to rubygems

    rake release

* if you remain stuck at "Pushed git commits and tags", the task may silently wait for your password. Check this if it's the case:

    https://github.com/carlhuda/bundler/issues/980

* you can list changes using github:

    https://github.com/activewarehouse/activewarehouse-etl/compare/release-0.9.1...master