the test as written fails if it's the last day of the month because
the two tallies that are added span two different periods.
Change-Id: I294397278508035ce640500fc3b1b0ffd82b9b71
projects
Currently, to generate invoices we are listing all projects. This is
problematic because we decided that elements like e.g. coupons should be
calculated per user. We want to have
more user oriented processing. With this change to prepare invoice
elements we are:
* listing Stripe customers
* listing projects for each customer
* processing projects to create project records
* calculating coupons per customer
* calculating credit spending per customer
Change-Id: I48b0063e44e4d301f97c87ecffb342649359968a
