coleifer/peewee ? reverse-engineered prompt

I want you to build a small, easy to learn Python ORM like Peewee.

It should feel simple to use, let me define models with fields, create tables, save rows, and write expressive queries with filters, joins, ordering, grouping, pagination, updates, and counts. It needs to work with SQLite, MySQL, MariaDB, and PostgreSQL, and also have asyncio support using the standard async drivers so I can use it in async apps too.

Please include a clean core library, a few useful extensions, basic migration support, and some example code that shows a tiny app with users and posts or tweets. Add tests for the important behavior, and make sure the README explains how to install it and get started quickly.

If you need to check current docs or driver details, look them up online.