Validation failed Class must exist
Try the following:
belongs_to :city, optional: trueAccording to the new docs:
4.1.2.11 :optional
If you set the :optional option to true, then the presence of theassociated object won't be validated. By default, this option is setto false.
This comes a bit late but this is how to turn off this by default in rails 5:
config/initializers/new_framework_defaults.rb
Rails.application.config.active_record.belongs_to_required_by_default = falseIn case you don't want to add optional: true to all your belongs_to.
I hope this helps!
You need to add the following to the end of the belongs_to relationship statement:
optional: trueIt is possible to set this on a global level so that it works in the same way as older versions of rails, but I would recommend taking the time to manually add it to the relationships that really need it as this will cause less pain in the future.