Improve Rails subtransactions Elastic watcher and add runbook
Description
This merge request improves rails subtransactions Elastic watcher:
- Ensure that we do not fire duplicated alerts for the same transactions with subtransactions detected
- Improve Slack notification message a bit.
- Add a basic runbook describing what to do when someone sees such notification.
Example
(Sidekiq logs link has been fixed in the diff and the runbook link has been updated too)
Edited by Grzegorz Bizon