Added README.

README

+# VideoLAN docker images
+
+VideoLAN docker images are used in [Jenkins] jobs to provide static build environments.
+
+On push, the [Docker Images Job] will launch and figure out the images that need to be rebuilt.
+
+The results will be available on VideoLAN docker registry under registry.videolan.org:5000/$tag.
+
+If you require a new Linux distro to be a base of your future image(-s), please put it under videolan-base/ directory.
+
+   [Gulp]: <http://gulpjs.com>
+   [Jenkins]: <//jenkins.videolan.org>
+   [Docker Images Job]: <https://jenkins.videolan.org/job/Infrastructure/job/Docker%20images/>