DOCS-730 add CONTRIBUTING.md to git repo

Author: Ed Costello

CONTRIBUTING.md

@@ -0,0 +1,27 @@
+Contributing to the MongoDB Documentation Project
+=================================================
+
+We welcome your contributions to the MongoDB documentation project.
+The primary site is http://docs.mongodb.org/ and translated versions
+of the site are available in [Japanese – 日本人](http://jp.docs.mongodb.org/) 
+and [Chinese – 中文](http://cn.docs.mongodb.org/).
+
+
+MongoDB documentation is distributed under a 
+[Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported](http://creativecommons.org/licenses/by-nc-sa/3.0/)
+license.
+10gen, Inc. retains the copyright on MongoDB documentation and ask that
+you complete a [MongoDB/10gen Contributor Agreement](http://www.10gen.com/contributor) 
+before we can accept your pull request.
+
+Please review the following documents for our style, conventions, 
+processes and practices for the MongoDB Documentation:
+
+* [Style and Conventions](meta.style-guide.rst)
+* [Practices and Processes](meta.practices.rst)
+* [Organization](meta.organization.rst)
+* [Building and Deploying MongoDB Documentation](meta.build.rst)
+
+Do not hesitate to open a ticket in our [Jira](https://jira.mongodb.org/browse/DOCS) project
+or to contact the [documentation team](mailto:[email protected])
+if you have any questions.