Add CONTRIBUTING

CONTRIBUTING.md

+## Developer Certificate of Origin + License
+
+By contributing to GitLab B.V., You accept and agree to the following terms and
+conditions for Your present and future Contributions submitted to GitLab B.V.
+Except for the license granted herein to GitLab B.V. and recipients of software
+distributed by GitLab B.V., You reserve all right, title, and interest in and to
+Your Contributions. All Contributions are subject to the following DCO + License
+terms.
+
+[DCO + License](https://gitlab.com/gitlab-org/dco/blob/master/README.md)
+
+_This notice should stay as the first item in the CONTRIBUTING.md file._
+
+
+## Project License
+
+You can view this projects license in [LICENSE.md](LICENSE)
+
+
+## Contributer Resources
+
+Thank you for your interest in contributing to GitLab. 
+
+For a first-time step-by-step guide to the contribution process, see our
+[Contributing to GitLab](https://about.gitlab.com/community/contribute/) page.
+
+You may also find these resources useful: 
+- [Documentation for community contributions](https://docs.gitlab.com/ee/development/contributing/#contribute-to-gitlab) 
+- [Security Scanner documentation](https://docs.gitlab.com/ee/development/integrations/secure.html) 
+
+## Contributer Code of conduct
+
+We want to create a welcoming environment for everyone who is interested in contributing.
+Visit our [Code of Conduct page](https://about.gitlab.com/community/contribute/code-of-conduct/) 
+to read our community pledge and standards.
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