Subscriptions

The following new features:
* Table Listing of Payments for the admin to see charges
* Event handling of succeeded and failed charges
* Implementation of user account lockout when charges fail

Could not get stubbing of responses that StripeEvent makes of Stripe to work.

If you add `user` here you can access it throughout the rest of the class without using the `@`. I suggest you do this and then go and change all other instances of `@user`