Add docker-compose.yml to be used for compile tests

Ideally this will be expanded in order to simplify compilation tests of
DAHDI on supported distributions.

Signed-off-by: Shaun Ruffell <sruffell@sruffell.net>

test/docker/centos6

@@ -0,0 +1,10 @@
+FROM centos:6
+
+RUN yum update -y
+RUN yum install -y \
+        gcc \
+        git \
+        make \
+        wget
+RUN yum install -y kernel-devel
+CMD ["/source/test/test-build.sh"]