Hey @atlantis, thanks for the PR this is a great addition ❤️ !

Adds a save method that only inserts/updates upon successful validation - insert and update behavior are unaffected.

Nice, and if users want to add validation with the regular insert/update methods they can use hooks (before_insert, before_update) anyway.

One side-effect of the way I wrote this is that you can't have a model class inherit from another non-abstract model class...

I think we can work around that by dropping the inherited macro. The argument of the block passed to the validate methods will always typed as the superclass+, but it is actually correct since the validators can be set from any class in the hierarchy. They can be force casted by the user anyway with .as if needed.

I would also like to make Validation optional (like the Versioning module) so people using Moongoon can pick another validation library if they want to.

I have made some changes based on what I wrote above on a separate branch (I don't know if there is better way to contribute to an external PR, maybe this?)

If you are cool with the changes then we'll also need to document everything properly at some point 😉.

Great! Looks like there's a conflict so I may let you resolve that if that's OK to make sure the correct parts get kept...

And I'll work on documentation in the next few days - do you want it on the main Readme or just documented in the API docs?

Looks like there's a conflict so I may let you resolve that if that's OK to make sure the correct parts get kept

Sure, I'll look into it!

do you want it on the main Readme or just documented in the API docs

I you could handle the API docs it would be great, and as a follow up I'll add a paragraph in the readme.