Add to Stripe product an option on creation of subscription for tax

Options required are:

  1. none: for current behaviour
  2. inclusive or exclusive: as discussed here Automatically collect tax on subscriptions

My use case is to have AU-GST inclusive as a line item on on receipts.

Access to Stripe tax is an opt-in that can be requested here https://stripe.com/en-au/tax

Currently it appears that when a Stripe subscription using Ghost is created then it can be modified/updated via the dashboard to include tax for subsequent receipts.

I would be prepared to make or assist with a pull request for change, but first would required some help/guidance with how stripe product is created and best approach to modifying admin UI to add the options.