Merge pull request #42182 from markuskowa/pgbackup-18.03

nixos-18.03/pgbackup: Fix bug in postgresql-backup module that causes to fail

nixos/modules/services/backup/postgresql-backup.nix

@@ -9,7 +9,7 @@ let
 
   postgresqlBackupCron = db:
     ''
-      ${config.services.postgresqlBackup.period} root ${config.services.postgresql.package}/bin/pg_dump ${db} | ${gzip}/bin/gzip -c > ${location}/${db}.gz
+      ${config.services.postgresqlBackup.period} root ${config.services.postgresql.package}/bin/pg_dump ${db} -U postgres | ${gzip}/bin/gzip -c > ${location}/${db}.gz
     '';
 
 in