I needed a minimal Docker image with CmdStan for unit testing, and found the the existing ones were abandonned and/or lacking a CI setup themselves (sorry if I missed something), so I put together
Docker image: https://hub.docker.com/r/tkpapp/cmdstan-docker/
The image is tested with CI on Travis (for compilation of the example model). It is based on debian:jessie with only the necessary extras installed, including a working compiler toolchain.