Thanks for the quick reply, I'll keep digging and let you know what I find.
Great tutorial. I wanted to pick your brain for a second. I followed your tutorial to the letter aside from using rails 5.0.2 and Bootstrap V4. For some reason when in the process of resubscribing a customer who needs to update to a new payment method using the "Use a different card" button, the hidden form only appears for a second and then disappears. I've checked my code against yours on Github and everything appears in order. If I click into one of the form fields before it disappears, the form will not go away but when I click on the submit button, the customers card is not updated. Any thoughts?