Write a simple TODO app using FastAPI, that lets a user
add TODOs, list their TODOs, delete TODOs, and update TODOs.
Include a `__main__` section which will run this app
using uvicorn. The python module where I save this code
will be called `main.py`.
Create & activate virtual environment
$ python3 -m venv venv
$ source venv/bin/activate
$ pip install -r requirements.txt
python3 main.py