diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,1 +1,7 @@
-2019 Feb 3 - Initial release, v1.0.0.0
+1.0.0.1 - 2019 Feb 3
+
+  * Add documentation
+
+1.0.0.0 - 2019 Feb 3
+
+  * Initial release
diff --git a/leanpub-concepts.cabal b/leanpub-concepts.cabal
--- a/leanpub-concepts.cabal
+++ b/leanpub-concepts.cabal
@@ -1,7 +1,7 @@
 cabal-version: 2.0
 
 name: leanpub-concepts
-version: 1.0.0.0
+version: 1.0.0.1
 
 synopsis: Types for the Leanpub API
 category: Web
diff --git a/library/Leanpub/Concepts.hs b/library/Leanpub/Concepts.hs
--- a/library/Leanpub/Concepts.hs
+++ b/library/Leanpub/Concepts.hs
@@ -64,6 +64,9 @@
 
 > https://leanpub.com/your_book/c/black_friday
 
+(Don't just give the code at the end of the coupon to your potential customers,
+since there's nowhere to type it in on the checkout form.)
+
 >>> :set -XOverloadedStrings
 >>> couponURL (BookSlug "your_book") (CouponCode "black_friday")
 "https://leanpub.com/your_book/c/black_friday"