Support for subscription-like data

I have a question about how to display data. The example in the documentation is about orders, which have a create date, and show how easy it is to graph the orders per month. That’s great!

I’ve got a slightly different use case. I have subscription-like data; my data looks like this:

Customer | Product | start_date | end_date
============================================
123      | basic   | 2015-01-01 | 2015-12-31
123      | plus1   | 2015-06-01 | 2015-12-31
411      | basic   | 2015-03-01 | 2015-05-15
516      | basic   | 2015-02-01 | 

And I want to plot how many products I have active for a given week or month.
What would be the best way to model this in Metabase?