class Students::RegistrationsController <  Devise::RegistrationsController

    def create
       @student = build_resource
       super
    end
end

Merit.setup do |config|
   config.checks_on_each_request = true
   config.orm = :active_record
   config.user_model_name = 'Student'
end

badge_id = 0
[{
  id: (badge_id = badge_id+1),
  name: 'just-registered'
}, {
  id: (badge_id = badge_id+1),
  name: 'best-unicorn',
  custom_fields: { category: 'fantasy' }
}].each do |attrs|
  Merit::Badge.create! attrs
end