Create CONTRIBUTING.md

CONTRIBUTING.md

@@ -0,0 +1,26 @@
+# Contributing to Eclipse Sprotty
+
+Thank you for your interest in the Sprotty project! The following is a set of guidelines for contributing to Sprotty.
+
+## Code of Conduct
+
+This project is governed by the [Eclipse Community Code of Conduct](https://github.com/eclipse/.github/blob/master/CODE_OF_CONDUCT.md). By participating, you are expected to uphold this code.
+
+## Communication
+
+The following communication channels are available:
+
+ * [GitHub issues](https://github.com/eclipse/sprotty/issues) - for bug reports, feature requests, etc.
+ * [Eclipse community forum](https://www.eclipse.org/forums/index.php/f/443/) - for questions
+ * [Gitter chat](https://gitter.im/eclipse/sprotty) - for questions and project-related discussion
+ * [Developer mailing list](https://accounts.eclipse.org/mailing-list/sprotty-dev) - for organizational issues (e.g. elections of new committers)
+
+In case you have a question, please look into the [documentation in the Wiki](https://github.com/eclipse/sprotty/wiki) first. If you don't find any answer there, feel free to use the chat, forum or issues to get help.
+
+## How to Contribute
+
+Before your pull request can be accepted, you must electronically sign the [Eclipse Contributor Agreement](https://www.eclipse.org/legal/ECA.php).
+
+Unless you are an [elected committer of the Sprotty project](https://projects.eclipse.org/projects/ecd.sprotty/who), you must include a `Signed-off-by` line in the commit message. This line can be generated with the [-s flag of git commit](https://git-scm.com/docs/git-commit#Documentation/git-commit.txt--s). By doing this you confirm that your contribution conforms to the Eclipse Contributor Agreement.
+
+For more information, see the [Eclipse Foundation Project Handbook](https://www.eclipse.org/projects/handbook/#resources-commit).