Update CONTRIBUTING.md

- Fixed broken link to the How To Contribute to and Open Source Project on GitHub (issue #109)
- Reformatted page a little

fix #109

CONTRIBUTING.md

@@ -1 +1,6 @@
-**Working on your first Pull Request?** You can learn how from this *free* series [How to Contribute to an Open Source Project on GitHub](https://egghead.io/series/how-to-contribute-to-an-open-source-project-on-github) 
+# Contributing information
+
+An issue reports are good, but PR are better!
+
+* [PR welcomed!](https://makeapullrequest.com/)
+* **Working on your first Pull Request?** You can learn how from this *free* series [How to Contribute to an Open Source Project on GitHub](https://egghead.io/courses/how-to-contribute-to-an-open-source-project-on-github)