Some users connect PostgREST to the wrong PostgreSQL instance - likely because they are not even aware that another instance is running. By using the standard port 5432 instead of 5433, we avoid this problem. The user will be made aware very early that they have another postgresql instance running - and can solve the problem at this stage. If they decide to change the port, they are much more likely to remember that in the later stages of the tutorial, too. Resolves https://github.com/PostgREST/postgrest-docs/issues/304