refactor ios payload structure

lib/pushnotificationsservice.js

@@ -128,10 +128,15 @@ PushNotificationsService.prototype._sendPushNotifications = function(notificatio
                 "notId": Math.floor(Math.random() * 100000) + 1
               }
             };
-
             opts.ios = {
-              "alert": content.plain.body,
-              "sound": "default"
+              "alert": {
+                "title": content.plain.subject,
+                "body": content.plain.body
+              },
+              "sound": "default",
+              "payload": {
+                "walletId": sjcl.hash.sha256.hash(notification.walletId)
+              }
             };
             return next(err, opts);
           }, next);