feat: オリジナルの作成日時追加（ #101 ） (#117)

#101 オリジナルの作成日時（より前）の自動設定

#101 余白追加

#101 余白追加

#101 オリジナルの作成日時，フォームにフィールド追加

#101 マイグレとコントローラ

Co-authored-by: miteruzo <miteruzo@naver.com>
Reviewed-on: #117

backend/db/migrate/20250909075500_add_original_created_at_to_posts.rb

@@ -0,0 +1,6 @@
+class AddOriginalCreatedAtToPosts < ActiveRecord::Migration[8.0]
+  def change
+    add_column :posts, :original_created_from, :datetime, after: :created_at
+    add_column :posts, :original_created_before, :datetime, after: :original_created_from
+  end
+end

backend/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_07_29_210600) do
+ActiveRecord::Schema[8.0].define(version: 2025_09_09_075500) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -83,6 +83,8 @@ ActiveRecord::Schema[8.0].define(version: 2025_07_29_210600) do
     t.bigint "parent_id"
     t.bigint "uploaded_user_id"
     t.datetime "created_at", null: false
+    t.datetime "original_created_from"
+    t.datetime "original_created_before"
     t.datetime "updated_at", null: false
     t.index ["parent_id"], name: "index_posts_on_parent_id"
     t.index ["uploaded_user_id"], name: "index_posts_on_uploaded_user_id"