readme: tweak title and add test page link

Author: chase-moskal

readme.md

@@ -1,7 +1,7 @@
 
 ![Authduo.org](https://i.imgur.com/Pr6ILnz.png)
 
-# 🗽 Free Passports for Everybody at [Authduo.org](https://authduo.org/)
+# 🗽 Free Auth for Everybody at [Authduo.org](https://authduo.org/)
 
 [Authduo.org](https://authduo.org/) is an app where users can create and manage digital login passports.
 
@@ -25,6 +25,8 @@ You can add a *"Login with Authduo"* button to your website, allowing users to l
 
 ## 🪪 [Authduo.org](https://authduo.org/) Login Button
 
+Try out the login button at the [Federated Test Page](https://authduo.org/federated/)
+
 ### Easy HTML Installation
 
 *Choose this installation method if you don't know any better.*