The yhub database ran under its own yhub role. Every other database in
this stack uses the backend's dev credentials, dinum/pass, which is also
what CI already uses for this database; only the database name stays
apart, since it is a separate database on a separate server.
The url the collaboration server connects with moves into the same file,
beside the credentials it repeats, written once rather than twice — the
yhub service reads the file as well. A yhub-postgres.local override is
created like for the other env files, and the healthcheck asks about
POSTGRES_DB and POSTGRES_USER like the other two do instead of naming the
role.
POSTGRES_USER only takes effect on a fresh initdb, so an existing stack
needs its yhub-pgdata volume dropped and `make migrate-yhub` re-run; the
volume holds local document state only.
Signed-off-by: Kevin Jahns <kevin.jahns@protonmail.com>
