Can't add coupon to offer

[freakinhuge]

When trying to apply a coupon to an offer that is not deferrable, an error is thrown saying amount is nil. The coupon partial should probably not be rendered for a non-deferrable offer if you can't apply a coupon to non-deferrable offers or handle the fact that amount is nil when submitted from the coupon form for a non-deferrable offer.

[franzejr]

What @loldlm1 did was: "If an offer is not deferrable, then we can't apply coupons".

This should be like this, @adamdill ? Just making sure before merging his PR.

[franzejr]

@loldlm1, what you did was just not show the coupon partial when we have a deferrable offer. This is not correct, after talking with @adamdill. We need to be able to apply coupons when the offer is deferrable.

Here are two flows we need to make sure we have(you can add these as tests - spinach):

1. No coupons on offers without amounts:

• Given an offer exists
• And the offer doesn’t have an amount (ie a tithe)
• Then we should not be able to apply a coupon to that offer

2. Coupons should work on deferrable offers

• Given an offer exists
• And the offer is defferable
• Then we should be able to apply a coupon to that offer

Can you do that?

Thanks!