Create clientSet.playerCount method

main.go

@@ -66,8 +66,12 @@ func (clients clientSet) broadcast(events ...event) {
 	}
 }
 
+func (clients clientSet) playerCount() int {
+	return len(clients.clients)
+}
+
 func (clients clientSet) playerCountEvent(offset int) event {
-	playerCount := len(clients.clients) + offset
+	playerCount := clients.playerCount() + offset
 	var data string
 	if playerCount == 0 {
 		data = "No players online."