- Cop: Rails/RelativeDateConstant
- raises offense if Constant is relative data (ie: since, ago)
- Reason: relative data will be evaluated only once
- BUT here, Date should not be evaluated in a class method, and have a different
- value for each call. But the data should be the same for an instance
- Therefore: move the ago in init method
- Cf. https://docs.rubocop.org/rubocop-rails/cops_rails.html#railsrelativedateconstant
- Since there is no constant to be called form a class, but a date from an instance, the
spec has been modified accordingly. The RemoveTransientData.new.call had to be splitted.