Make vendor dir customizable (#122)

Author: dnna

Bootstraps/Symfony.php

@@ -46,7 +46,7 @@ public function getApplication()
         if (file_exists($appAutoLoader)) {
             require $appAutoLoader;
         } else {
-            require './vendor/autoload.php';
+            require $this->getVendorDir().'/autoload.php';
         }
 
         // environment loading as of Symfony 3.3
@@ -90,6 +90,20 @@ public function getApplication()
 
         return $app;
     }
+    
+    /**
+    * Returns the vendor directory containing autoload.php
+    *
+    * @return string
+    */
+    protected function getVendorDir()
+    {
+        if (getenv('COMPOSER_VENDOR_DIR') && file_exists(getenv('COMPOSER_VENDOR_DIR'))) {
+            return getenv('COMPOSER_VENDOR_DIR');
+        } else {
+            return './vendor';
+        }
+    }
 
     /**
      * Does some necessary preparation before each request.