One of your colleagues is assigned this ticket to implement a small web app:
Create a small web app that allows users to sign up. Each user can optionally provide their age and their country. After signing up, users should be able to follow other users, and see a list of who they follow. Additionally, users should be able to configure account settings like whether they want to enable two-factor-authentication. Finally, special admin users should have the ability to change a user's username or delete their account.
The coworker asks you to review their proposed SQLite schema. Review their work in the PR.