def self.containing_ids(id)
    joins(:containings).select("containings.id").where("containers.id" => id, "containings.is_excluded" => false).map(&:id)
  end
  def containing_ids
    self.class.containing_ids id
  end

  def self.containing_blacklisted_ids(id)
    joins(:containings).select("containings.id").where("containers.id" => id, "containings.is_excluded" => true).map(&:id)
  end
  def containing_blacklisted_ids
    self.class.containing_blacklisted_ids id
  end