Grafana 4.0 gives us Alerts so let set them up.
Lets create a new dashboard WebPageTest alerts. Start with alerts for:
- SpeedIndex median
- Start render median
And have them by browser, logged-in status, desktop/mobile and first/second view. We need https://phabricator.wikimedia.org/T151197 to be merged first before we go live for real, but we can start testing setting alerts before.