Update database-schema.adoc

docs/manual/src/docs/asciidoc/_includes/appendix/database-schema.adoc

@@ -28,7 +28,7 @@ create table authorities (
 create unique index ix_auth_username on authorities (username,authority);
 ----
 
-=== For Oracle database
+==== For Oracle database
 [source]
 ----
 CREATE TABLE USERS (