MAGETWO-91200: Update documentation for PageBuilder EAP

- update contributing documentation

Author: Igor Melnikov

app/code/Magento/PageBuilder/docs/CONTRIBUTING.md

@@ -15,22 +15,23 @@ The Magento 2 development team will review all issues and contributions submitte
 3. Commits must be accompanied by meaningful commit messages.
 4. PRs which include bug fixing, must be accompanied with step-by-step description of how to reproduce the bug.
 3. PRs which include new logic or new features must be submitted along with:
-* Unit/integration test coverage (we will be releasing more information on writing test coverage in the near future).
-* Proposed [documentation](http://devdocs.magento.com) update. Documentation contributions can be submitted [here](https://github.com/magento/devdocs).
+* Unit/integration test coverage where applicable.
+* Updated documentation in the module directory `app/code/PageBuilder/docs`.
 4. For large features or changes, please [open an issue](https://github.com/magento/magento2/issues) and discuss first. This may prevent duplicate or unnecessary effort, and it may gain you some additional contributors.
-5. All automated tests are passed successfully (all builds on [Travis CI](https://travis-ci.org/magento/magento2) must be green).
+5. All automated tests are passed successfully locally. After PR submitted Magento team will run builds on continuous integration environment.
 
 ## Contribution process
 
 If you are a new GitHub user, we recommend that you create your own [free github account](https://github.com/signup/free). By doing that, you will be able to collaborate with the Magento 2 development team, “fork” the Magento 2 project and be able to easily send “pull requests”.
 
-1. Search current [listed issues](https://github.com/magento/magento2/issues) (open or closed) for similar proposals of intended contribution before starting work on a new contribution.
+1. Search current [listed issues](https://github.com/magento/magento2-page-builder/issues) on GitHub (open or closed) and [list of known issues](roadmap.md#Known Issues) on our roadmap for similar proposals of intended contribution before starting work on a new contribution.
+2. Please contact us in Slack chanel if you want to work on issue from [list of known issues](roadmap.md#Known Issues).
 2. Review the [Contributor License Agreement](https://magento.com/legaldocuments/mca) if this is your first time contributing.
 3. Create and test your work.
-4. Fork the Magento 2 repository according to [Fork a repository instructions](http://devdocs.magento.com/guides/v2.0/contributor-guide/contributing.html#fork) and when you are ready to send us a pull request – follow [Create a pull request instructions](http://devdocs.magento.com/guides/v2.0/contributor-guide/contributing.html#pull_request).
+4. Fork the Magento 2 repository according to [Fork a repository instructions](http://devdocs.magento.com/guides/v2.0/contributor-guide/contributing.html#fork) and when you are ready to send us a pull request – follow [Create a pull request instructions](http://devdocs.magento.com/guides/v2.0/contributor-guide/contributing.html#pull_request). Instructions written for `https://github.com/magento/magento2` repository, but they also apply to `https://github.com/magento/magento2-page-builder`.
 5. Once your contribution is received, Magento 2 development team will review the contribution and collaborate with you as needed to improve the quality of the contribution.
 
 ## Code of Conduct
 
 Please note that this project is released with a Contributor Code of Conduct. We expect you to agree to its terms when participating in this project.
-The full text is available in the repository [Wiki](https://github.com/magento/magento2/wiki/Magento-Code-of-Conduct).
+The full text is available in the repository [Wiki](https://github.com/magento/magento2/wiki/Magento-Code-of-Conduct).