class ActiveModel::Serializer::Associations::HasMany

def serialize
  associated_object.map do |item|
    find_serializable(item).serializable_hash
  end
end

def serialize_ids
  # Use pluck or select_columns if available
  # return collection.ids if collection.respond_to?(:ids)
  associated_object.map do |item|
    item.read_attribute_for_serialization(:id)
  end
end