Add contributing guide

CONTRIBUTING.md

@@ -0,0 +1,24 @@
+# How to Contribute
+
+If you're interested in contributing, take a look at the general [contributer's guide](https://github.com/Microsoft/ApplicationInsights-Home/blob/master/CONTRIBUTING.md) first.
+
+## Run Test
+
+Make sure you have bundler installed, you can install it by ```gem install bundler```. And run ```bundler install``` once to install all dependencies.
+
+Run ```rake test```.
+
+## Contributing
+
+This 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.
+
+When you submit a pull request, a CLA-bot will automatically determine whether you need
+to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the
+instructions provided by the bot. You will only need to do this once across all repositories using our CLA.
+
+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.