First check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn't find it.
• I searched the FastAPI documentation, with the integrated search.
• I already searched in Google "How to X in FastAPI" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answ

Should add a section to the docs for third-party examples and guides using Mangum

There should be routes that trigger an email for "forgot" and "reset" password options. These can be celery tasks but probably need a separate container for a simple SMTP server in order to send the emails.

The fullstack Vue project has an example of a containerized SMTP server.

HI again ! Last issue for the period I believe ;-)

Would you mind adding a quick doc about how to extend the metrics ? The FastAPI / starlette ones are a very good basis, but I'ld like to add some related to my app.

For example I have a Postgres database, I want to add the number of active subscription in the metrics, aka the result of a SELECT * FROM subscription WHERE active == 1 that wo