add header note

Author: gingerwizard

docs/en/integrations/data-sources/postgres.md

@@ -7,4 +7,6 @@ hide_title: false
 
 import PostgreSQL from '@site/docs/en/integrations/data-ingestion/dbms/postgresql/connecting-to-postgresql.md';
 
+A full migration guide for PostgreSQL to ClickHouse, including advice on data modeling and equivalent concepts, can be found [here](/docs/en/migrations/postgresql/overview). The following describes how to connect ClickHouse and PostgreSQL.
+
 <PostgreSQL/>