Hi team, I have a couple of questions regarding Medplum: Is there anyone who can guide us on how to create custom tables in Medplum? We're using the Medplum Client SDK, but some of our use cases are not fully covered by the default schema. We'd like to know if it's possible to write our own tables and how to integrate them. Could someone explain how FHIR resource storage works if we're using our own local PostgreSQL database? We're planning to go with self-hosting at an enterprise level, and we'd like to get a rough estimate of any potential costs associated with FHIR resource storage in this setup. Thanks cc: @rahul1 @reshma