Fix readme links to alternative projects

Author: soupmatt

README.rdoc

@@ -4,9 +4,9 @@ Unfortunately, those of us who have been maintaining this project no longer have
 
 Otherwise, we recommend you consider one of the following alternatives:
 
-{rack-cas}[/biola/rack-cas]
+{rack-cas}[https://github.com/biola/rack-cas]
 
-{omniauth-cas}[/dlindahl/omniauth-cas]
+{omniauth-cas}[https://github.com/dlindahl/omniauth-cas]
 
 {<img src="https://secure.travis-ci.org/rubycas/rubycas-client.png" alt="Build Status" />}[http://travis-ci.org/rubycas/rubycas-client]
 {<img src="https://codeclimate.com/badge.png" />}[https://codeclimate.com/github/rubycas/rubycas-client]