message: Added README on alerting.
diff: @@ -131,3 +131,6 @@ Or `git clone ssh://git@gitrest.westus2.cloudapp.azure.com/home/git/prague` for
  From there you can use your git repository management tool of choice to inspect the various documents and revisions
  stored in the repository.
  +
  +## Alerting
  +We are using [elastalert](https://github.com/Yelp/elastalert) plugin to send email alerts on production failures and errors. The plugin scans data from elasticsearch and looks for anomalies/patterns/spikes. Checkout the [documentation](http://elastalert.readthedocs.io/en/latest/) for creating new alert rules.
  