Changes for version 0.11
- Added a --slow_threshold option, to consider queries slow if they have been running for longer than the given value (seconds). Now we highlight slow queries in bold yellow, and log all the slow queries to a `pgtop.log` file.
- Added a --slack_webhook option, to automatically notify a slack channel if a query crosses the slow threshold runtime value. All the information about the slow query including the SQL will be included in the slack message.
display PostgreSQL performance info like `top'