docs: add debugging doc

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

docs/debugging.md

@@ -0,0 +1,30 @@
+Debugging libmraa                         {#debugging}
+=================
+
+This page contains a few debugging tip, when filing an issue please go through
+this list as if you don't it's the first thing we'll have to ask you to do.
+
+### Version
+
+Getting the exact version of libmraa you're running is really important to us.
+The best way to get this is to call mraa_get_version() or mraa.getVersion(). If
+mraa returns x.x.x-dirty then your version was not built from a git tree or you
+built out of tree (see our building doc) - or you don't have git installed.
+
+### Syslog
+
+mraa logs pretty much everything that goes wrong to syslog, these days it'll go
+to the systemd journal usually so check with `sudo journalctl -f` whilst
+running your app or check all libmraa messages with `journalctl -t libmraa`.
+Grab all the messages from the initialisation message right up to your last
+one, using a pastebin is always a good idea, I like dpaste.com. If your system
+does not have systemd likely your log is in /var/log/messages or similar.
+
+### Common Errors
+
+* Not running as root
+* Incorrect IO numbers, mraa uses physical connector pin numbering see your
+  platform doc for details
+* Unsuported platform
+* Using the wrong pin, check pin capabilities
+