README.md in peddler-0.11.1 vs README.md in peddler-0.12.0

@@ -41,9 +41,21 @@
 export MWS_MERCHANT_ID=...
 export AWS_ACCESS_KEY_ID=...
 export AWS_SECRET_ACCESS_KEY=...
 ```
 
+### MWS Authorized Tokens
+
+If instantiating a client for another seller, you have to provide the `MWSAuthToken` generated for you by the latter:
+
+```ruby
+client = MWS.orders(
+  marketplace_id: "...",
+  merchant_id:    "...",
+  auth_token:     "..."
+)
+```
+
 ## Usage
 
 ### Cart Information
 
 With the MWS Cart Information API, you can retrieve shopping carts that your Amazon Webstore customers have created. The Cart Information API enables you to programmatically integrate Amazon Webstore cart information with your CRM systems, marketing applications, and other systems that require cart data.