diff --git a/README.md b/README.md
index 51c3553..cca57b3 100644
--- a/README.md
+++ b/README.md
@@ -2,3 +2,4 @@
 - `git checkout step-0`: initial state (clean Rails app with no additional gems)
 - `git checkout step-1`: we have installed and configured the dotenv-rails and shopify_app gems
 - `git checkout step-2`: the app registers a `products/update` HTTP webhook
+- `git checkout step-3`: in response to a product update, the app sets a tag