doc: Add a contributing document

CONTRIBUTING.adoc

@@ -0,0 +1,41 @@
+= Contributing to Mobile NixOS
+
+You don't need to write code to help contributing with Mobile NixOS.
+
+As Mobile NixOS is a superset on top of NixOS, you should read the link:https://github.com/NixOS/nixpkgs/blob/master/.github/CONTRIBUTING.md[
+contributing guidelines] of the NixOS project. Many of the points apply just
+the same with Mobile NixOS.
+
+
+== Opening issues
+
+Issues you face when using or working with Mobile NixOS should be filed on
+link:https://github.com/NixOS/mobile-nixos/issues[the project's issue tracker].
+
+First verify an existing, open, and recent issue matching your exact problem
+doesn't already exist. In case of doubt, always open a new issue. Sometimes
+vaguely reported symptoms are from different sources and it is easier to manage
+when different issues are opened.
+
+When describing the issues you face, please provide the most information you
+can. For sharing logs, please share them as link:https://gist.github.com/[Gists]
+so the issue does not get bogged down.
+
+== Porting
+
+ifdef::env-github[]
+See the <<doc/porting-guide.adoc#,Device Porting Guide>>.
+endif::[]
+ifndef::env-github[]
+See the <<porting-guide.adoc#,Device Porting Guide>>.
+endif::[]
+
+Once a port has been made for a new device, link:https://github.com/NixOS/mobile-nixos/pulls[open a Pull Request].
+
+== Packaging software
+
+Unless it is related to the abstraction of device specifics, packaging should
+be done upstream at the link:https://github.com/NixOS/nixpkgs[Nixpkgs] project.
+
+Mobile NixOS is a superset of NixOS, all the software that is in NixOS is
+available for Mobile NixOS.

doc/default.nix

@@ -38,6 +38,17 @@ stdenv.mkDerivation {
 
     EOF
 
+    # The title needs to be first
+    head -n1 ${../CONTRIBUTING.adoc} > contributing.adoc
+
+    # Then we're adding our common stuff
+    cat >> contributing.adoc <<EOF
+    include::_support/common.inc[]
+    EOF
+
+    # Then continuing with the file.
+    tail -n +2 ${../CONTRIBUTING.adoc} >> contributing.adoc
+
     if [ ! -e index.adoc ]; then
     cat >> index.adoc <<EOF
     = Main Page