update readme

Author: SophieDeBenedetto

README.md

@@ -314,7 +314,12 @@ Flushing stats at  Sun Mar 22 2020 13:36:41 GMT-0400 (Eastern Daylight Time)
 
 - [X] Success/failure web request response instrumentation
 * LiveView metrics with channel joined and channel handled_in
-* VM metrics with polling
+* Three custom metrics:
+  * Worker polling
+  * Custom event polling
+  * Telemetry plug
+  * Success/failure indicator 
+- [X] VM metrics with polling
 * Visualize DD reporting by using DD formatter but running regular statsd, grab log statement from error message
 
 ## Notes