Refactor: `is_active` カラムを削除し `inactivated_at` に統一#1744

yasulab merged 10 commits intomaincoderdojo-japan/coderdojo.jp:mainfrom

refactor-to-merge-inactive-into-inactivated-columnscoderdojo-japan/coderdojo.jp:refactor-to-merge-inactive-into-inactivated-columnsCopy head branch name to clipboard