validates (ActiveModel::Validations::ClassMethods)

validates (ActiveModel::Validations::ClassMethods) - APIdock:

This method is a shortcut to all default validators and any custom validator classes ending in ‘Validator’. Note that Rails default validators can be overridden inside specific classes by creating custom validator classes in their place such as

Full article: http://apidock.com/rails/ActiveModel/Validations/ClassMet...