Probably a good idea to treat `*.Dockerfile` as dockerfile format as well. In general, it's better to use the `Dockerfile` part as an extension rather than a basename.
Signed-off-by: Andrew Pennebaker <andrew.pennebaker@gmail.com>
Upstream-commit: 2f5146ba1d413a7a07943648fd37e73f076361be
Component: engine
The contrib directory contains scripts, images, and other helpful things
which are not part of the core docker distribution. Please note that they
could be out of date, since they do not receive the same attention as the
rest of the repository.