Add Docker demo image to build

This lets us build and deploy a docker demo image as part of the normal build process.

Change-Id: Ie6ca6667fecb8d0b6f758b97ccc0b12110c833ea
Reviewed-on: https://asterix-gerrit.ics.uci.edu/294
Reviewed-by: Chris Hillery <ceej@lambda.nu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Till Westmann <tillw@apache.org>
diff --git a/asterix-docker/docker/.gitattributes b/asterix-docker/docker/.gitattributes
new file mode 100644
index 0000000..399e6a7
--- /dev/null
+++ b/asterix-docker/docker/.gitattributes
@@ -0,0 +1 @@
+*.adm binary