Add workflow entered event documentation

Author: brexis

README.md

@@ -167,6 +167,11 @@ class BlogPostWorkflowSubscriber
      */
     public function onEnter($event) {}
 
+    /**
+     * Handle workflow entered event.
+     */
+    public function onEntered($event) {}
+
     /**
      * Register the listeners for the subscriber.
      *
@@ -193,6 +198,11 @@ class BlogPostWorkflowSubscriber
             'Brexis\LaravelWorkflow\Events\EnterEvent',
             'App\Listeners\BlogPostWorkflowSubscriber@onEnter'
         );
+
+        $events->listen(
+            'Brexis\LaravelWorkflow\Events\EnteredEvent',
+            'App\Listeners\BlogPostWorkflowSubscriber@onEntered'
+        );
     }
 
 }