How to do this simple update with SeaORM?

This is the update in question:

UPDATE nations
SET gold = (gold + 10)
WHERE id = 5;

I know I can do raw SQL queries, but it's annoying having to revert to that so often.

I've been feeling pretty mixed on whether I like this ORM or not. On one hand, it feels intuitive and has a lot of functionality. On the other, when I get stuck, the docs are not helpful... It's just the easiest, most straightforward examples and that's it.