Add more metrics collection

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

supervisor/stats.go

@@ -1,23 +1,5 @@
 package supervisor
 
-import "github.com/rcrowley/go-metrics"
-
-var (
-	ContainerStartTimer    = metrics.NewTimer()
-	ContainersCounter      = metrics.NewCounter()
-	EventsCounter          = metrics.NewCounter()
-	EventSubscriberCounter = metrics.NewCounter()
-)
-
-func Metrics() map[string]interface{} {
-	return map[string]interface{}{
-		"container-start-time": ContainerStartTimer,
-		"containers":           ContainersCounter,
-		"events":               EventsCounter,
-		"events-subscribers":   EventSubscriberCounter,
-	}
-}
-
 type StatsEvent struct {
 	s *Supervisor
 }