Add link to tutorial for specifics on including Stripe keys

docs/docs/process-payments-with-stripe.md

@@ -16,7 +16,7 @@ To get started, create a [Stripe account](https://dashboard.stripe.com/register)
 
 ### Getting your Stripe test keys
 
-Once logged into the Stripe dashboard, you can find your API keys under the Developers menu. Before you activate your account, you'll only have access to your test API keys. You'll need to use your publishable and secret keys as described in the documentation for any plugins, starters, or other integrations you use. Test keys allow you to test your Stripe integration without making real payments. To access your live API keys, activate your account.
+Once logged into the Stripe dashboard, you can find your API keys under the Developers menu. Before you activate your account, you'll only have access to your test API keys. You'll need to use your publishable and secret keys as described in the documentation for any plugins, starters, or other integrations you use. Test keys allow you to test your Stripe integration without making real payments. To access your live API keys, activate your account. The e-commerce tutorial describes how to [add your Stripe keys when using the gatsby-source-stripe plugin](/tutorial/ecommerce-tutorial/#add-the-stripe-source-plugin).
 
 While testing, you must use the key(s) that include the word test. For production code, you will need to use the live keys. As the names imply, your publishable key may be included in code that you share publicly (for example, on the frontend, and in GitHub), whereas your secret key should not be shared with anyone or committed to any public repo. It’s important to restrict access to this secret key because anyone who has it could potentially read or send requests from your Stripe account and see information about charges or purchases or even refund customers.