How do you generate the resolver layer in code instead of memory?

I need to modify the default CRUD resolvers that are currently stored in memory when `buildGraphbackAPI` is called. The readme has the follow tidbit:

* Generates an unopiniated GraphQL resolver layer (as code or in memory)

I do not see how to use the graphback-cli anywhere in the documentation that would instead generate these resolvers into the codebase.

Any help would be appreciated.