add: show bad entry on URL invalid error

scripts/dburl-parser.sh

@@ -16,6 +16,7 @@ queryless_url="${DB_URL%%\?*}";
 schema="${queryless_url%//*}";
 if test "${schema}" = "${queryless_url}"; then
     echo >&2 "database URLs must start with schema (i.e.: mysql://)"\
+    && echo >&2 "URL_INVALID_ERROR: \"${DB_URL}\""\
     && exit 2;
 fi
 schemaless_url=${queryless_url#*//};