As a way to workaround more or less improper usage of roundup-mailgw and
apache integration the simplest way should set a group (roundup) and
have both postfix and apache inside it and then make sure that the db
directory is owned by that group (e.g. roundup:roundup).

The problem is that the blobfile.py doesn't preserve the group and
instead saves files and dirs as either apache:apache or postfix:postfix.

The proper solution would be have a transport recipe for postfix and
avoid mod_python or even better have a single roundup daemon queried by
the various agents/front-ends.