Docs: Add debug guide

This patch introduces a simple debug guide to help new developers.

Author: Akrog

CONTRIBUTING.md

@@ -74,6 +74,14 @@ section](README.md#getting-started):
 - [Running in OpenShift with external
   dependencies](docs/dev/custom-image-dependencies.md)
 
+### Debugging
+
+When working on the cinder-operator there will be times where things won't work
+as expected and we'll need to debug things.
+
+In the [debugging article](docs/dev/debug.md) we present some ideas to help you
+figure things out.
+
 ### Pull Requests
 
 While the pull request flow is used for submitting new issues and for