Rails: rubocop disable Class has too many lines error

Try

class Xzy  # rubocop:disable Metrics/ClassLength

when disabling, be sure to enable again

# rubocop:disable ClassLength
class LongClass
end
# rubocop:enable ClassLength

references:

1. rubocop/lib/rubocop/cop/metrics/class_length.rb

2. disabling-cops-within-source-code