Documenting Queries with foreign keys requests

[lmick002]

Improve documentation

https://github.com/supabase/postgrest-kt

Documentation showing how to use foreign keys within postgres-kt select statements would be beneficial, especially for those not experienced with the library.

Reference code showing the foreign key usage would be greatly appreciated.
Thanks!

[lmick002]

For more context here's our query that we're trying to adapt to the postrgres-kt library from the javascript library.

`

const { data: profile, error } = await db.from("profiles")
.select(
*, tools: tools_user_id_fkey(*), shops: shops_user_id_fkey(*) )
.eq('id', id)
.is('deleted_at', null)
.single();`

But it's not returning the tools & shops related to the profile

[kevcodez]

I need to have a look at how the JS client does this, definitely haven't tested it. If you figure this out, feel free to contribute a PR as time is pretty tight on my side ATM