Use JSON to send initialize data

Author: ibrahimlawal

modules/gateways/callback/paystack.php

@@ -63,7 +63,8 @@
         $ch,
         CURLOPT_HTTPHEADER,
         array(
-        'Authorization: Bearer '. trim($secretKey)
+        'Authorization: Bearer '. trim($secretKey),
+        'Content-Type: application/json'
         )
     );
 
@@ -72,7 +73,7 @@
     curl_setopt(
         $ch,
         CURLOPT_POSTFIELDS,
-        http_build_query(
+        json_encode(
             array(
             "amount"=>$amountinkobo,
             "email"=>$email,