RuboCop currently has several official & unofficial support channels.

For questions, suggestions and support refer to one of them. Please, don't use the support channels to report issues, as this makes them harder to track.

Gitter

Most internal discussions about the development of RuboCop happen on its gitter channel. You can often find RuboCop's maintainers there and get some interesting news from the project's kitchen.

Mailing List

The official mailing list is hosted at Google Groups. It's a low-traffic list, so don't be too hesitant to subscribe.

Freenode

If you're into IRC you can visit the #rubocop channel on Freenode. It's not actively monitored by the RuboCop maintainers themselves, but still you can get support from other RuboCop users there.

Stackoverflow

We're also encouraging users to ask RuboCop-related questions on StackOverflow.

When doing so you should use the RuboCop tag (ideally combined with the tag ruby).

Bountysource

If you're willing to pay for some feature to be implemented you can use Bountysource to place a bounty for the work you want to be done.