Update README.md

Author: monkstone

README.md

@@ -29,8 +29,13 @@ Many of the vanilla processing example sketches have been translated to ruby-pro
 
 4. [JBox2D][]
 
+### User contributions are most welcome
+[Contributions][] add your [own][]
+
 [Learning Processing with Ruby]:https://github.com/ruby-processing/learning-processing-with-ruby
 [Nature of Code Examples in ruby]:https://github.com/ruby-processing/The-Nature-of-Code-Examples-in-Ruby
+[Contributions]:https://github.com/ruby-processing/Example-Sketches/tree/master/samples/contributions
+[own]:https://github.com/ruby-processing/CONTRIBUTIONS.md
 [Basic]:https://github.com/ruby-processing/Example-Sketches/tree/master/samples/processing_app/basics
 [structure]:https://github.com/ruby-processing/Example-Sketches/tree/master/samples/processing_app/basics/structure
 [objects]:https://github.com/ruby-processing/Example-Sketches/tree/master/samples/processing_app/basics/objects