message: Adding links to contributing.md
diff: @@ -48,3 +48,5 @@ _List of available examples_
  ## Contributing
  You can contribute by submitting [issues tickets](http://github.com/jacomyal/sigma.js/issues) and proposing [pull requests](http://github.com/jacomyal/sigma.js/pulls). Make sure that tests and linting pass before submitting any pull request.
  +
  +You can also browse the related documentation [here](./CONTRIBUTING.md).
  