Adding content_available option to Notification for iOS use

Author: Nandor Huszar

src/Notification.php

@@ -13,6 +13,7 @@ class Notification extends Message
     private $sound;
     private $clickAction;
     private $tag;
+    private $content_available;
 
     public function __construct($title = '', $body = '')
     {
@@ -77,6 +78,12 @@ public function setTag($tag)
         return $this;
     }
 
+    public function setContentAvailable($content_available)
+    {
+        $this->content_available = $content_available;
+        return $this;
+    }
+
     public function jsonSerialize()
     {
         $jsonData = $this->getJsonData();
@@ -101,6 +108,9 @@ public function jsonSerialize()
         if ($this->tag) {
             $jsonData['tag'] = $this->tag;
         }
+        if ($this->content_available) {
+            $jsonData['content_available'] = $this->content_available;
+        }        
         return $jsonData;
     }
-}
+}