etc/postgresql/9.1/main/pg_ident.conf

   1 # MAPNAME  SYSTEM-USERNAME       PG-USERNAME
   2 admin      postgres              postgres
   3 admin      root                  postgres
   4 role       postgres              davical_dba
   5 role       php_davical           davical_app
   6 user       postgres              agendav
   7 user       root                  roundcube
   8 user       /^php_(.*)$           \1
   9 user       /^(.*)$               \1