Adapted Contributing.md

CONTRIBUTING.md

 # How to contribute
 
+Please refer to our [Developer Guide](https://opengeosys.org/docs/devguide) for
+instructions on contributing to OpenGeoSys:
 
-
-## Getting Started
-
-* Make sure you have a [GitHub account](https://github.com/signup/free)
-* Fork the repository on GitHub
-
-## Making Changes
-
-* Create a topic branch from where you want to base your work.
-  * This is usually the master branch.
-  * Only target other branches if you are certain your fix must be on that
-    branch.
-  * To quickly create a topic branch based on master; `git branch
-    my_topic_branch master` then checkout the new branch with `git
-    checkout my_topic_branch`.  Please avoid working directly on the
-    `master` branch.
-* Make commits of logical units.
-* Make sure your code conforms to the [styleguide][styleguide].
-* Check for unnecessary whitespace with `git diff --check` before committing.
-* Make sure your commit messages are in the proper format.
-
-````
-    One sentence summary.
-
-    Detailed description of the commit ...
-    ....
-````
-
-* TODO: Test your changes
-
-## Submitting Changes
-
-* Push your changes to a topic branch in your fork of the repository.
-* Submit a pull request to the main repository.
-
-# Additional Resources
-
-* [General GitHub documentation](http://help.github.com/)
-* [GitHub pull request documentation](http://help.github.com/send-pull-requests/)
-* [OGS Styleguide][styleguide]
-
-[styleguide]: http://ufz.github.com/styleguide/cppguide.xml
+- The [Getting Started](https://www.opengeosys.org/docs/devguide/getting-started/introduction/)-section
+  guides you through setting up a development environment.
+- In [Development Workflows](https://www.opengeosys.org/docs/devguide/development-workflows/branching-model/)
+  you learn about our development model.