Add service customer

Author: thiphamyp

Resources/config/services.xml

@@ -14,6 +14,7 @@
         <service id="zoho.api.addon" class="Zoho\Subscription\Api\Addon" parent="zoho.api.manager"></service>
         <service id="zoho.api.plan" class="Zoho\Subscription\Api\Plan" parent="zoho.api.manager"></service>
         <service id="zoho.api.invoice" class="Zoho\Subscription\Api\Invoice" parent="zoho.api.manager"></service>
+        <service id="zoho.api.customer" class="Zoho\Subscription\Api\Customer" parent="zoho.api.manager"></service>
 
         <service id="zoho.array.cache" class="Doctrine\Common\Cache\ArrayCache"></service>