### New features

* [#586](https://github.com/rubocop/rubocop-rails/pull/586): Add new `Rails/RootJoinChain` cop. ([@leoarnold][])
* [#571](https://github.com/rubocop/rubocop-rails/issues/571): Add `Rails/DurationArithmetic` cop. ([@pirj][])
* [#594](https://github.com/rubocop/rubocop-rails/pull/594): Add `Rails/RedundantPresenceValidationOnBelongsTo` cop. ([@pirj][])
* [#568](https://github.com/rubocop/rubocop-rails/issues/568): Add `Rails/SchemaComment` cop. ([@vitormd][])

### Changes

* [#591](https://github.com/rubocop/rubocop-rails/issues/591): Add `change_column` check to `Rails/ReversibleMigration`. ([@mattmccormick][])
* Add `remove_reference` check to `Rails/ReversibleMigration`. ([@mattmccormick][])
* [#576](https://github.com/rubocop/rubocop-rails/pull/576): Mark `Rails/TimeZone` as unsafe auto-correction from unsafe. ([@koic][])
* [#582](https://github.com/rubocop/rubocop-rails/pull/582): Unmark `AutoCorrect: false` from `Rails/RelativeDateConstant`. ([@koic][])
* [#580](https://github.com/rubocop/rubocop-rails/pull/580): Unmark `AutoCorrect: false` from `Rails/UniqBeforePluck`. ([@koic][])

[@leoarnold]: https://github.com/leoarnold
[@pirj]: https://github.com/pirj
[@vitormd]: https://github.com/vitormd
[@mattmccormick]: https://github.com/mattmccormick
[@koic]: https://github.com/koic
