message: Update contributing.md to include information about the CLA
diff: +# Instructions for Contributing Code
  +
  +## 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.
  +
  +## Legal
  +
  +If your contribution is more than 15 lines of code, you will need to complete a Contributor License Agreement (CLA). Briefly, this agreement testifies that you are granting us permission to use the submitted change according to the terms of the project's license, and that the work being submitted is under appropriate copyright.
  +
  +Please submit a Contributor License Agreement (CLA) before submitting a pull request. You may visit https://cla.azure.com to sign digitally. Alternatively, download the agreement ([Microsoft Contribution License Agreement.docx](https://www.codeplex.com/Download?ProjectName=typescript&DownloadId=822190) or [Microsoft Contribution License Agreement.pdf](https://www.codeplex.com/Download?ProjectName=typescript&DownloadId=921298)), sign, scan, and email it back to <cla@microsoft.com>. Be sure to include your github user name along with the agreement. Once we have received the signed CLA, we'll review the request.
  +
  # Contributing to Botkit
  The following is a set of guidelines for contributing to Botkit.
  @@ -50,3 +62,4 @@ possible with your report. If you can, please include:
  * Use the imperative mood ("Move cursor to..." not "Moves cursor to...")
  * Limit the first line to 72 characters or less
  * Reference issues and pull requests liberally
  +
  