build: adds docker build script for development purposes.

This is just a convenience tool that enables anyone to pull in the code
and build it without installing to many dependancies (only Docker).

Signed-off-by: Chris Lapa <chris@lapa.com.au>

dbuild.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+set -e
+
+docker build -t gtk-sharp-debian9 .
+
+docker run gtk-sharp-debian9 ${@}