From the Ruby style guide:
# bad
class FooError < StandardError
end
# okish
class FooError < StandardError; end
# good
FooError = Class.new(StandardError)
This cop does that, but only for error classes (classes where the
superclass ends in 'Error'). We have empty controllers and models, which
are perfectly valid empty classes.
This adds a Rubocop rule to enforce the use of
add_concurrent_foreign_key instead of the regular add_foreign_key
method. This cop has been disabled for existing migrations so we don't
need to change those.