add stripe libs through composer

composer.json

@@ -123,7 +123,8 @@
         "zendframework/zend-config": "~3.0",
         "zendframework/zend-feed": "~2.6|^3.0",
         "zendframework/zend-http": "~2.6|^3.0",
-        "zendframework/zend-soap": "~2.6|^3.0"
+        "zendframework/zend-soap": "~2.6|^3.0",
+        "stripe/stripe-php": "*"
     },
     "require-dev": {
         "behat/behat": "~3.5",

plugin/buycourses/src/process_confirm.php

@@ -412,7 +412,6 @@ switch ($sale['payment_type']) {
             $stripeParams = $plugin->getStripeParams();
             $currency = $plugin->getCurrency($sale['currency_id']);
 
-            require_once '../gateways/stripe-php/init.php';
             \Stripe\Stripe::setApiKey($stripeParams['secret_key']);
             \Stripe\Stripe::setAppInfo("ChamiloBuyCoursesPlugin");
 

plugin/buycourses/src/stripe_response.php

@@ -15,8 +15,6 @@ $payload = @file_get_contents('php://input');
 $sig_header = $_SERVER['HTTP_STRIPE_SIGNATURE'];
 $event = null;
 
-require_once '../gateways/stripe-php/init.php';
-
 try {
     $event = \Stripe\Webhook::constructEvent(
         $payload, $sig_header, $stripeParams['endpoint_secret']