class TalkPreference < ActiveRecord::Base self.primary_key = :unique_id serialize :talks, Array before_create :assign_new_unique_id def include?(id) talks.include? id.to_s end private def assign_new_unique_id self.unique_id = SecureRandom.uuid self.hashed_unique_id = Digest::SHA1.hexdigest(self.unique_id) end end