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contributing.md

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+Contributions of all kinds are welcome!
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+**Reporting Issues**
+
+\* Please use [ZK tracker](https://tracker.zkoss.org/projects/ZKCK) to report issues.
+
+\* Before creating an issue, please review open issues to avoid a duplicate.
+
+\* If you have a question, not an issue, please discuss it in [ZK Forum](https://forum.zkoss.org/questions/).
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+**Contributing codes**
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+If you wish to contribute code, please create a corresponding issue [in tracker](https://tracker.zkoss.org/projects/ZKCK) and a pull request containing the ID of the issue from the tracker with your comments. Your request will be reviewed before being merged.
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+**License and Copyright**
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+This project is created and maintained by Potix Corporation. 
+
+Any contributed content is licensed under the same license and terms as the project license. By contributing your code, you certify that you created the content and agree to surrender your copyright of the contributed code to Potix. 
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+
+For any inquiries and questions, please contact us at info@zkoss.org.