class ActiveModel::Serializer::Associations::HasOne

def plural_key
  key.to_s.pluralize.to_sym
end

def serialize
  object = associated_object
  object && find_serializable(object).serializable_hash
end

def serialize_ids
  if object = associated_object
    object.read_attribute_for_serialization(:id)
  else
    nil
  end
end

def serialize_many
  object = associated_object
  value = object && find_serializable(object).serializable_hash
  value ? [value] : []
end