Allow dynamic schema_names

[Xervon]

PR Info

I'd like to be able to switch schema_names at runtime to switch between development and production environments.

This PR changes the schema_name parameter of the DeriveEntityModel and DeriveEntity macros to take a syn::Expr instead of a syn::Lit. As far as I can tell this shouldn't break any existing code.

Since I haven't done much work with derive macros before, I couldn't quite tell how to integrate the change into the test suite. I'd appreciate hints on how to add them.

New Features

• Accept syn::Expr as a schema_name

[tyt2y3]

Thanks for the contribution. Can you add some tests illustrating the behaviour you wanted to achieve? i.e.

schema_name parameter of the DeriveEntityModel and DeriveEntity macros to take a syn::Expr