fixed an issue with the docker entrypoint script.

docker/docker-entrypoint.sh

@@ -25,6 +25,11 @@ wait_for_postgres() {
 	host="${PAPERLESS_DBHOST}"
 	port="${PAPERLESS_DBPORT}"
 
+	if [[ -z $port ]] ;
+	then
+		port="5432"
+	fi
+
 	while !</dev/tcp/$host/$port ;
 	do