Update Feature proposal - detailed.md

.gitlab/issue_templates/Feature proposal - detailed.md

@@ -31,6 +31,14 @@ Personas are described at https://about.gitlab.com/handbook/marketing/product-ma
 * [Eddie (Content Editor)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#eddie-content-editor)
 -->
 
+### Metrics 
+
+<!-- How are you going to track uage of this feature? Think about user behavior and their interaction with the product. What indicates someone is getting value from it?
+
+Create tracking issue using the Snowplow event tracking template. See https://gitlab.com/gitlab-org/gitlab/-/blob/master/.gitlab/issue_templates/Snowplow%20event%20tracking.md
+
+-->
+
 ### User experience goal
 
 <!-- What is the single user experience workflow this problem addresses?