fix Coinbase saying price can't be blank
more concise and working CoinbaseController#invoice
Spree::CoinbasePayments resource
Working CoinbaseController#notify
CoinbaseController#payment_method was changed to find the payment method by type because there was no `params[:payment_method_id]` being passed. Is there a better way to do this?
Update Spree::PaymentMethod::Coinbase to allow order.next in Spree::CoinbaseController#notify
Note that `attr_accessible` on line 6 of coinbase.rb doesn't work in Rails 4. I had to replace it with a static method that returns my API key in my local copy to get it to work.