asyncdb

Your task is to develop a small, fully-functional asynchronous web application using Python that connects to a PostgreSQL database and allows users to manage a simple 'To-Do' list. This application will serve as a practical example of utilizing the 'asyncdb' package for asynchronous database operations. Here’s a detailed breakdown of the steps and features you should implement:

1. **Setup**: Begin by setting up your Python environment. Ensure you have the latest versions of Flask for web development and asyncdb installed. Also, set up a local PostgreSQL database instance.
2. **Database Connection**: Use asyncdb to establish an asynchronous connection to your PostgreSQL database. Implement the necessary functions to create a table called `todos` if it doesn't already exist, which will store tasks with columns such as `id`, `title`, `description`, and `completed`.
3. **CRUD Operations**: Implement Create, Read, Update, and Delete operations on the `todos` table using asyncdb. These operations should be performed asynchronously to demonstrate the benefits of asyncdb over traditional synchronous database interactions.
4. **Web Interface**: Using Flask, create a simple web interface where users can:
   - View all their current tasks.
   - Add new tasks.
   - Mark tasks as completed or delete them.
5. **User Authentication**: For simplicity, implement basic user authentication. Each user should be able to log in and only see their own tasks. Store user credentials securely in the database.
6. **Testing**: Write tests to ensure that all CRUD operations work correctly and that the web application behaves as expected under different scenarios.
7. **Documentation**: Provide clear documentation on how to set up and run the application, including instructions on how to use asyncdb effectively within the project.

By following these steps, you will create a robust, scalable application that leverages the power of asyncdb for efficient database management. This project will not only help you understand the capabilities of asyncdb but also give you hands-on experience with building asynchronous applications in Python.