[D] FIX dbprepare: port 5432 was useful!

was removed in d8932f3d828baf77273
to be very clean, it should only be used during "dbprepare" phase, but I
found no option to do that from docker-compose only

docker-compose.yml

@@ -10,6 +10,8 @@ services:
             - POSTGRES_USER=ttrss
             - POSTGRES_PASSWORD=password-dev
             - POSTGRES_DB=ttrss
+        ports:
+            - 5432:5432
 
     tt-rss:
         image: feedati/tt-rss:latest