Generate pgsql db structure from schema

[tshemsedinov]

[nechaido]

@tshemsedinov do we need to create Postgres's Domain for each domain? This sounds like a nice idea, but I'm sure that we'll add data validation on a globalstorage level, and this will make type constraints in Postgres redundant.

[tshemsedinov]

@nechaido Such an approach would be good for PG based application, when all business logic, constraints and queries will be executed in PG. We use PG just for persistent storage and need no domains.