fix: simple ORM for one struct and foreign references work

Currently, all methods declared in the Georm trait are available.

If a struct has an ID pointing towards another entity, the user can
create a get method to get the entity pointed at from the database
too (local one-to-one relationship).

I still need to implement remote one-to-one relationships (one-to-one
relationships when the ID of the remote object is not available
locally).

I still need to also test and debug one-to-many relationships (ID of
the remote entiies not available locally) and many-to-many
relationships (declared in a dedicated table).

For now, IDs in all cases are simple types recognized by SQLx that are
not arrays. Options are only supported when explicitely specified for
one-to-one relationships.

Cargo.toml

@@ -34,6 +34,9 @@ features = ["postgres", "runtime-tokio", "macros", "migrate"]
 sqlx = { workspace = true }
 georm-macros = { workspace = true }
 
+[dev-dependencies]
+rand = "0.9"
+
 [workspace.lints.rust]
 unsafe_code = "forbid"