update readme

Author: xiongcc

README.md

@@ -40,3 +40,5 @@ This project has been started by [@NikolayS]() on 2023-09-26 https://twitter.com
 - 0017 [How to determine the replication lag](https://github.com/xiongcccc/postgres-howto/blob/master/How%20to%20determine%20the%20replication%20lag.md)
 - 0018 [Over-indexing](https://github.com/xiongcccc/postgres-howto/blob/master/Over-indexing.md)
 - 0019 [How to import CSV to Postgres](https://github.com/xiongcccc/postgres-howto/blob/master/How%20to%20import%20CSV%20to%20Postgres.md)
+- 0020 [How to use pg_restore](https://github.com/xiongcccc/postgres-howto/blob/master/How%20to%20use%20pg_restore.md)
+- 0021 [How to set application_name without extra queries](https://github.com/xiongcccc/postgres-howto/blob/master/How%20to%20set%20application_name%20without%20extra%20queries.md)