you need to run the database migrations in order to use a real database like Postgres

Thank you, can you suggest how it can be done using golang? I found method runMigration - https://github.com/authzed/spicedb/blob/6e72bb745f400d494820bad5e3787d3161b0ac72/pkg/cmd/migrate.go#L101 But it is using internal package and I can not use it in my package.

well, first question: why are you running it against Postgres if it is in-memory?