s2i: use root in favor of pgsql user

Signed-off-by: Tomas Tomecek <[email protected]>

Author: TomasTomecek

latest/root/usr/share/container-scripts/postgresql/README.md

@@ -246,7 +246,7 @@ with configuration in `~/image-configuration/` run:
 
 
 ```
-$ s2i build ~/image-configuration/ postgresql new-postgresql
+$ s2i build --assemble-user root ~/image-configuration/ postgresql new-postgresql
 ```
 
 The directory passed to `s2i build` should contain one or more of the