Add set_all! and unset_all! for relation scope

[killondark]

Hi @kenn. I done realize requested feature. Check please.

[killondark]

@kenn, up.

[jake]

was surprised to realize scoped calls to set_all don't respect the scope. any update on getting this merged in and released?

[killondark]

@jake, nope. No updates.

[kenn]

Passing scope in as an arg is not good. I'll come up with something when I have time — expect some time in July.

[jake]

Sounds good, thank you! Just wanted to point out that the way it currently works is arguably pretty broken and error-prone. If you call set_all on a scope, it just ignores that scope and applies it globally to the entire table. Not sure if this is any easier than just making it apply the scope, but feels like even throwing an exception if you call it on a scope would be good.