Add "How to contribute"

Draft of a Highlevel Contributing guideline like described in winjs#30.

CONTRIBUTING.md

@@ -0,0 +1,34 @@
+# Contributing
+
+The Winstrap project welcomes contributions and suggestions.  Most contributions require you to agree to a
+Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us
+the rights to use your contribution. For details, visit https://cla.microsoft.com.
+
+This needs to only be done once for any Microsoft open source project.
+
+# Code of Conduct
+
+This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/).
+For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or
+contact [opencode@microsoft.com](mailto:opencode@microsoft.com) with any additional questions or comments.
+
+# How to contribute
+
+There are many ways that you can contribute to the Winstrap project:
+* Submit a bug
+* Verify fixes for bugs
+* Submit a code fix for a bug
+* Submit a feature request
+* Tell others about the WinJS project
+* Tell the developers how much you appreciate the project
+
+## Contributing to README and Wiki
+
+You do not need to sign a Contribution License Agreement if you are just contributing to the README or the Wiki. 
+By submitting a contribution to the README or the Wiki, you are contributing it under the 
+[Creative Commons CC0 1.0 Universal Public Domain Dedication](http://creativecommons.org/publicdomain/zero/1.0/).
+
+## Contributing Code
+
+Note that all code submissions will be reviewed and tested by the team, and only those that meet an extremely 
+high bar for both quality and design/roadmap appropriateness will be merged into the source.