Symlink README to stripe-haskell/README

The README.md has the following snippet:

import Web.Stripe
import Web.Stripe.Coupon

main :: IO ()
main = do
  let config = StripeConfig "secret key"
  result <- stripe config $ updateCoupon (CouponId "couponid") [("key1", "value2"), ("key2", "value2")]
  case result of
    Right coupon -> print $ couponMetaData coupon
    Left stripeError -> print stripeError

which doesn't compile, because StripeKey has no IsString instance. As I was submitting a PR, I realized that @bitemyapp had already fixed it for stripe-haskell/README.md in 538aae94e812a050698bbd432af2ec6b0fc58cb1. Both READMEs look very similar, maybe symlink one to the other?

dmjio / stripe

Symlink README to stripe-haskell/README #82