Add a recording rule example for TPS
Add a recording rule example for TPS

Add a recording rule example for "Transactions Per Second".

[0]: https://dev.mysql.com/doc/refman/5.7/en/glossary.html#glos_transaction

roman-vynar/mysqld_exporter,roman-vynar/mysqld_exporter,prometheus/mysqld_exporter,prometheus/mysqld_exporter