Android Push Notification Setup

public function sendNotification($deviceid,$message){
//$id = 'efB8fsbfcYU:APA91bGyJ3oBYc79H5WgT-D6UW9RyDWtwImeWBWKx6RucRAK3iiGHfc4o74xm-Yc8M8vOIXtgafvSN1sl7kEfaHquVtpUNqU5VqQrhimNueTd5wL5VzBd66z41WNGT-a3LuRouWnitM-';
//$message = 'Test FCM message for Raviarsid';

$url = 'https://fcm.googleapis.com/fcm/send';
   $fields = array (
           'registration_ids' => array (
                   $deviceid
           ),
           'data' => array (
                   "message" => $message
           )
   );
   $fields = json_encode ( $fields );

   $headers = array (
           'Authorization: key=' . "AIzaSyA_QZ_27JoSVc1hehCI-4GKS2xFKYDBA8s",
           'Content-Type: application/json'
   );

   $ch = curl_init ();
   curl_setopt ( $ch, CURLOPT_URL, $url );
   curl_setopt ( $ch, CURLOPT_POST, true );
   curl_setopt ( $ch, CURLOPT_HTTPHEADER, $headers );
   curl_setopt ( $ch, CURLOPT_RETURNTRANSFER, true );
   curl_setopt ( $ch, CURLOPT_POSTFIELDS, $fields );

   $result = curl_exec ( $ch );
   //echo $result;
   curl_close ( $ch );
}