### New features

* Extract Rails cops from rubocop/rubocop repository. ([@koic][])
* [#19](https://github.com/rubocop/rubocop-rails/issues/19): Add new `Rails/HelperInstanceVariable` cop. ([@andyw8][])

[@koic]: https://github.com/koic
[@andyw8]: https://github.com/andyw8
