Add beta testing links to the README

Author: hawkrives

README.md

@@ -4,8 +4,8 @@
 The St. Olaf community, now in pocket size… rewritten in React Native.
 
 ## Download
-- [Android](https://play.google.com/store/apps/details?id=com.allaboutolaf)
-- [iOS](https://itunes.apple.com/us/app/all-about-olaf/id938588319)
+- [Android](https://play.google.com/store/apps/details?id=com.allaboutolaf) ([Sign up as a beta tester!](https://play.google.com/apps/testing/com.allaboutolaf))
+- [iOS](https://itunes.apple.com/us/app/all-about-olaf/id938588319) ([Sign up as a beta tester!](https://boarding-aao.heroku.com))
 
 ## Getting Started
 - Clone the repository