metrics.md in sapience-2.3.3

- old
+ new

@@ -43,10 +43,11 @@
 metrics.decrement("metric-key")
 metrics.count("metric-key", -3)
 metrics.histogram("metric-key", 2_500)
 metrics.gauge("metric-key", 1_000, {})
 metrics.event("metric-key", "description about event", {})
+metrics.event("metric-key", "description about event", {namespace: true})
 metrics.batch do
   metrics.event("metric-key", "description about event", {})
   metrics.increment("another-metric-key", 2)
 end
 ```
@@ -82,6 +83,27 @@
 occurred in one component, module or whole app. It's handy for event types that can occur in all modules of an app.
 We use it mainly for error metrics. Example:
 
 ```ruby
 metrics.increment('error', tags: %w(error_class:AccessDenied module:authentication component:permissions))
+```
+
+### Event Metric
+
+For the `event` metric the first parameter is `title` - string.
+By default it is not namespaced, however with option `namespace: true` it will automatically namespace it.  
+
+
+```ruby 
+metrics.event("metric-key", "description about event", {namespace: true})
+
+```
+Output: `app_name.environment.metric-key`
+
+#### Event Grouping
+
+In order to group similar events, use option: `aggregation_key`
+
+```ruby 
+metrics.event("metric-key", "description about event", {namespace: true, aggregation_key:true})
+
 ```