Updated WebApplication README to point to new source repo on GitHub.

Author: rts-rob

WebApplication/README.md

@@ -1,4 +1,9 @@
 # Serverless Web Application Workshop
 
-This module is now available at
-[https://webapp.serverlessworkshops.io](https://webapp.serverlessworkshops.io).
+This workshop is now available online at:
+[https://webapp.serverlessworkshops.io](https://webapp.serverlessworkshops.io)
+
+## Contributing
+
+The source for this workshop is available at:
+[https://github.com/aws-samples/aws-serverless-webapp-workshop](https://github.com/aws-samples/aws-serverless-webapp-workshop)