Basic support for selecting a group of products to highlight
set promotions by calling "Promotions.create :product => some_prod" in the console etc (no nice admin interface yet)
call Promotions.random_subset(n) to get n products
call Promotions.best_sellers(n, start = 1.week.ago, finish = Time.now) to get the n best sellers in the selected time period (default: the past week)
at present: just a table of ids, with no uniqueness checking
admin interface flag on each product? or drop-down list?
filter this by taxons??
maybe extend to "also bought"?