Merge pull request #479 from witold-gren/issue-478/updated-readme

updated README, added note about prom-metrics-check tool

Author: brancz

README.md

@@ -250,3 +250,8 @@ While the community has not yet fully agreed on alert severities and their to be
 * For more motivation, see
 "[The RED Method: How to instrument your services](https://kccncna17.sched.com/event/CU8K/the-red-method-how-to-instrument-your-services-b-tom-wilkie-kausal?iframe=no&w=100%&sidebar=yes&bg=no)" talk from CloudNativeCon Austin.
 * For more information about monitoring mixins, see this [design doc](https://docs.google.com/document/d/1A9xvzwqnFVSOZ5fD3blKODXfsat5fg6ZhnKu9LK3lB4/edit#).
+
+## Note
+
+You can use the external tool call [prom-metrics-check](https://github.com/ContainerSolutions/prom-metrics-check) to validate the created dashboards. This tool allows you to check if the metrics installed and used in Grafana dashboards exist in the Prometheus instance. 
+Please have a look at https://github.com/ContainerSolutions/prom-metrics-check.