task/CONTRIBUTING.md

• Bug reports and feature requests are welcome in the issues
• For questions and discussion there's the Slack room
• Pull Requests are welcome. For more complex changes and features it's recommended to open an issue first
• About 3 or 4 pull requests accepted one gets write access to the repo. Even then, possible backward incompatible changes should be discussed first in an issue or pull request
• Documentation contributions are as important as code contributions