title: Stripe - Apply coupon to customer or subscription?
body: <p>In the Stripe API Documentation, they show that you can apply a coupon on a Customer.</p>
  
  <pre><code>cust = Stripe::Customer.retrieve("cus_asdasdad")
  cust.coupon = "COUPONCODE"
  cust.save
  </code></pre>
  
  <p>However, you can also apply a coupon on a Subscription:</p>
  
  <pre><code>cust = Stripe::Customer.retrieve("cus_asdasdad")
  sub = cust.subscriptions.retrieve("sub_blablabla")
  sub.coupon = "COUPONCODE"
  sub.save
  </code></pre>
  
  <p>What is the difference between the two?  Essentially, I'd like to give a customer $15 off their next subscription charge, and only the next one.</p>