Adding contributing document

Author: cneill

doc/contributing.md

@@ -0,0 +1,23 @@
+# Contributing to DefectDojo
+
+There are a few things to keep in mind when developing your own code for
+DefectDojo
+
+## Modifying Application Settings
+
+0. You must keep
+[ansible/roles/webserver/templates/settings.j2][settings_template]
+up to date with [dojo/settings.dist.py][dojo_settings] as you make
+changes to your settings if you want to install via the Vagrant provisioning
+script, or if you want to submit a pull request to DefectDojo. You should define
+any additional variables needed upon install in
+[ansible/vars.yml][ansible_vars]
+
+0. If you want to make changes to the DefectDojo code and test it with Vagrant,
+you will need to change the `dd_git_repo` and/or `dd_git_branch` variables
+defined in [ansible/vars.yml][ansible_vars]
+
+
+[settings_template]: ../ansible/roles/webserver/templates/settings.j2 "Ansible settings template"
+[dojo_settings]: ../dojo/settings.dist.py "DefectDojo settings file"
+[ansible_vars]: ../ansible/vars.yml "Ansible variables file"