Upgrade to ZAF v2

[stevenmaguire]

This package supports Zendesk Apps Framework v1, which is currently in an end-of-life process. If you installed this pacakage before August 1, 2017 then you will be able to run the package in your Zendesk account until March 1, 2018. If you are attempting to install after August 1, 2017 it will not work.

This package needs to be upgraded to support Zendesk Apps Framework v2, for which there is a migration guide.

A branch has already been started to begin the migration. https://github.com/delivered/chargify-zendesk/tree/zaf-v2

• Fork the project from here https://github.com/delivered/chargify-zendesk
• Make the changes
• Test
• Submit pull request