add OAUTH CBT site

Author: lbertalot

Meli/meli.php

@@ -26,7 +26,8 @@ class Meli {
         "MPA" => "https://auth.mercadolibre.com.pa", // Panama
         "MPE" => "https://auth.mercadolibre.com.pe", // Peru
         "MPT" => "https://auth.mercadolibre.com.pt", // Prtugal
-        "MRD" => "https://auth.mercadolibre.com.do"  // Dominicana
+        "MRD" => "https://auth.mercadolibre.com.do",  // Dominicana
+        "CBT" => "https://global-selling.mercadolibre.com"  // CBT
     );
 
     /**