Subscription model

I’m curious if anyone has any examples they would like to share on how
to
implement tiered subscriptions. I’ve seen a few methods myself, but I’d
like
to know how others are doing it.

I’ve seen

User has_many :subscriptions
User has_one :current_subscription

I’ve also seen the subscription info stored as a hash. I don’t like that
as
much, but it is quick and dirty.

What I am really interested in is how you check for permissions?
Controller
level? Model level?

I’d appreciate any insight you have to offer. Thanks in advance!

-b