Using joins in query for subscriptions and customers

[800a7b32]

I am trying to get a list of all subscriptions that have been paid for offline (i.e. where the 'fake_processor' has been used).

Pay::Subscription.joins(:pay_customers).where(pay_customers: {processor: "fake_processor"}).where.not(processor_id: [nil, ""]) results in Can't join 'Pay::Subscription' to association named 'pay_customers'; perhaps you misspelled it?

How can I perform this join?