add DCO to the project (#81)

Signed-off-by: Clemens Grabmann <[email protected]>

CONTRIBUTING.md

@@ -0,0 +1,28 @@
+# Contributing to the project
+
+## Sign off Your Work
+
+The Developer Certificate of Origin (DCO) is a lightweight way for contributors to certify that they wrote or otherwise have the right to submit the code they are contributing to the project. Here is the full text of the [DCO](https://developercertificate.org/). Contributors must sign-off that they adhere to these requirements by adding a Signed-off-by line to commit messages.
+
+```
+This is my commit message
+
+Signed-off-by: Random J Developer <[email protected]>
+```
+
+See git help commit:
+
+```
+-s, --signoff
+Add Signed-off-by line by the committer at the end of the commit log
+message. The meaning of a signoff depends on the project, but it typically
+certifies that committer has the rights to submit this work under the same
+license and agrees to a Developer Certificate of Origin (see
+http://developercertificate.org/ for more information).
+```
+
+## How to Contribute
+
+1. Fork this repository, develop, and test your changes
+2. Remember to sign off your commits as described above
+3. Submit a pull request

README.md

@@ -411,3 +411,7 @@ autoConfigure {
 Each property here comes with an equivalent to the above mentioned sub-plugins. If you set a default value
 on the root module here, and override it with a more specific value in the sub-module, then the latter will
 always win.
+
+## Contributing
+
+-   [Contributing to the project](CONTRIBUTING.md)