updated read me to include optional dashboard alerts
@@ -162,7 +162,10 @@ and/or `alert_stale_results_hours` (alerts when tests haven't run recently).
You can also set `num_passes_to_disable_alert`.
In DashboardTab, set `alert_mail_to_addresses` (comma-separated list of email
-addresses to send mail to).
+addresses to send mail to). Additional options for alerts are `num_passes_to_disable_alert`
+(the number of consecutive test passes to close the alert), `subject` (custom subject for alert mails),
+`debug_url` (custom link for further context/instructions on debugging this alert), and `debug_message`
+(custom text to show for the debug link; `debug_url` is required for `debug_message` to appear).
These alerts will send whenever new failures are detected (or whenever the
dashboard tab goes stale), and will stop when `num_passes_to_disable_alert`
