Stripe API upgrade

[gbp]

What does this do?

Upgrades the Stripe API version used.

Why was this needed?

To hopefully help in migrating from Stripe plans to prices which in turn will help us add new prices and change existing subscriptions.

[gbp]

https://docs.stripe.com/changelog/2019-03-14/renames-date-field-invoices-created

There are a few changes to the invoice object:

• The date property has been renamed to created.

Need to change

alaveteli/app/views/alaveteli_pro/invoices/_invoice.html.erb

Line 2 in fb4d9f5

<strong><%= invoice.date.to_fs(:long) %></strong>

and

alaveteli/app/models/alaveteli_pro/invoice.rb

Line 17 in fb4d9f5

def date

Should also add test examples to catch this.

[gbp]

https://docs.stripe.com/changelog/2018-02-05/plans-link-individual-products-several-fields-moved

Each plan object is now linked to a product object .... The plan object ... and name attributes have been moved to product objects, and plan objects now have a nickname attribute.

Need to change

alaveteli/app/views/alaveteli_pro/plans/show.html.erb

Line 32 in fb4d9f5

<%= @plan.name %>

and

alaveteli/app/views/alaveteli_pro/subscriptions/_subscription.html.erb

Line 4 in fb4d9f5

<%= subscription.plan.name %>

Should also add test examples to catch this.

[gbp]

https://docs.stripe.com/changelog/2018-07-27/coupons-use-floats-specify-percent-off

The percent_off field of coupons was changed from Integer to Float, with a precision of two decimal places.

Need to check the calculations in

alaveteli/app/models/alaveteli_pro/subscription_with_discount.rb

Lines 74 to 80 in fb4d9f5

	def coupon_reduction(net)
	if coupon.amount_off
	BigDecimal((coupon.amount_off * 0.01), 0).round(2)
	else
	(net * coupon.percent_off / 100)
	end
	end

[gbp]

The above comments have been addressed. While I can write failing tests for them (stripe-ruby-mock doesn't enforce valid attributes, and it does expand Stripe resources) I have ensured they are all fixed.