update readme

Author: xiongcc

README.md

@@ -101,3 +101,5 @@ This project has been started by [@NikolayS]() on 2023-09-26 https://twitter.com
 - 0076 [How to find redundant indexes](https://github.com/xiongcccc/postgres-howto/blob/master/How%20to%20find%20redundant%20indexes.md)
 - 0077 [Postgres major upgrade without any downtime for a very large cluster running under heavy load](https://github.com/xiongcccc/postgres-howto/blob/master/Postgres%20major%20upgrade%20without%20any%20downtime%20for%20a%20very%20large%20cluster%20running%20under%20heavy%20load.md)
 - 0078 [How to estimate the YoY growth of a very large table using row creation timestamps and the planner statistics](https://github.com/xiongcccc/postgres-howto/blob/master/How%20to%20estimate%20the%20YoY%20growth%20of%20a%20very%20large%20table%20using%20row%20creation%20timestamps%20and%20the%20planner%20statistics.md)
+- 0079 [How to rebuild many indexes using many backends avoiding deadlocks](https://github.com/xiongcccc/postgres-howto/blob/master/How%20to%20rebuild%20many%20indexes%20using%20many%20backends%20avoiding%20deadlocks.md)
+- 0080 [How to find int4 PKs with out-of-range risks in a large database](https://github.com/xiongcccc/postgres-howto/blob/master/How%20to%20find%20int4%20PKs%20with%20out-of-range%20risks%20in%20a%20large%20database.md)