btrc-hub/backend/app/models/post_version.rb

class PostVersion < ApplicationRecord
  include VersionRecord

  belongs_to :post
  belongs_to :parent, class_name: 'Post', optional: true

  validates :url, presence: true

  validate :validate_original_created_range

  private

  def validate_original_created_range
    f = original_created_from
    b = original_created_before
    return if f.blank? || b.blank?

    if f >= b
      errors.add :original_created_before, 'オリジナルの作成日時の順番がをかしぃです．'
    end
  end
end