Changed the yardoc links,as old links are not taking to documentation pages,proper links for 0.10,0.9 and 0.8 in rubydoc

Author: domitian

README.md

@@ -7,11 +7,11 @@
 
 ## Documentation
 
-- [0.10 (master) Documentation](https://github.com/rails-api/active_model_serializers/tree/master)
+- [0.10 (master) Documentation](http://www.rubydoc.info/github/rails-api/active_model_serializers/v0.10.0.rc4)
   - [![API Docs](http://img.shields.io/badge/yard-docs-blue.svg)](http://www.rubydoc.info/github/rails-api/active_model_serializers)
   - [Guides](docs)
-- [0.9 (0-9-stable) Documentation](https://github.com/rails-api/active_model_serializers/tree/0-9-stable)
-- [0.8 (0-8-stable) Documentation](https://github.com/rails-api/active_model_serializers/tree/0-8-stable)
+- [0.9 (0-9-stable) Documentation](http://www.rubydoc.info/github/rails-api/active_model_serializers/0-9-stable)
+- [0.8 (0-8-stable) Documentation](http://www.rubydoc.info/github/rails-api/active_model_serializers/0-8-stable)
 
 ## About