$ heroku create
! You've reached the limit of 5 apps for unverified accounts.
! Add a credit card to verify your account.
どうやら、5つ以上作れないらしい（無料分では）
作成済みappの表示
$ heroku apps
=== My Apps
desolate-harbor-9190
evening-earth-3373
obscure-dawn-8322
still-escarpment-3902
tranquil-sea-3272
確かに5こ
古いappを削除しよう
$ heroku destroy --app desolate-harbor-9190
! WARNING: Potentially Destructive Action
! This command will destroy desolate-harbor-9190 (including all add-ons).
! To proceed, type "desolate-harbor-9190" or re-run this command with --confirm desolate-harbor-9190
もう一度、appIDの入力を求められたので入力して実行
desolate-harbor-9190
Destroying desolate-harbor-9190 (including all add-ons)... done
完了した
$ heroku create
Creating radiant-caverns-9976... done, stack is cedar
http://radiant-caverns-9976.herokuapp.com/ | git@heroku.com:radiant-caverns-9976.git
Git remote heroku added
できた〜☆