Creates a new `db_tasks.md` file that defines the database schema for the bot.
This documentation includes table definitions for:
- `users`: To store user information.
- `permissions`: To manage user permissions for specific actions.
- `welcome_flow_data`: To store data collected during the `/welcome` onboarding flow.
The file also explains how the bot will interact with these tables to manage users, permissions, and the onboarding process.
