Enable the `Rails/ApplicationRecord` cop

Description of the proposal

Enable the Rails/ApplicationRecord cop: https://github.com/rubocop-hq/rubocop/pull/4279

We're introducing various helpers in ApplicationRecord to support the CodeReuse/ActiveRecord cop, and to help engineers not feel the need to routinely disable it. As part of this, I just converted all our models to use ApplicationRecord instead of ActiveRecord::Base: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/10483

I think we should enable this cop to prevent any backsliding ;). It's also Rails5-standard: https://blog.bigbinary.com/2015/12/28/application-record-in-rails-5.html

  • Mention the proposal in the next backend weekly call and the #backend channel to encourage contribution
  • Proceed with the proposal once 50% of the maintainers have weighed in, and 80% of the votes are 👍
  • Once approved, mention it again in the next backend weekly call and the #backend channel

MRs

/cc @gitlab-org/maintainers/rails-backend

Edited by Nick Thomas