Todo App Link `404` in README.md Example Apps Section

[nelsonic]

Hey! 👋
Was just reading through your docs [looking good!] but noted that:
https://github.com/digitallyinduced/thin-backend/blame/6e376d3861370e58aea83dfe5eabf8f0a2924ed0/README.md#L221
links to: https://github.com/digitallyinduced/ihp-backend-todo-app which is 404

Should be: https://github.com/digitallyinduced/thin-backend-todo-app

[nelsonic]

PR: #51

[mpscholten]

Thanks, good catch 👍