I'm studying the possibility of developing new payment gateways inside Shopify. While I was researching I got into ActiveMerchant (https://github.com/activemerchant) which (as I understand) is a repository for payment gateways. I'm looking for a PHP development environment and as I see the repository contains Ruby modules.
Is there a way to develop Shopify Payment Gateways using PHP? If so can you please point me a "Getting started" document?