Add instruction supporing tvOS and watchOS

README.md

@@ -20,6 +20,7 @@ KeychainAccess is a simple Swift wrapper for Keychain that works on iOS and OS X
 - **[Support TouchID and Keychain integration (iOS 8+)](#touch_id_integration)**
 - **[Support Shared Web Credentials (iOS 8+)](#shared_web_credentials)**
 - Works on both iOS & OS X
+- watchOS and tvOS are supported
 
 ## :book: Usage