declare versions for Docker base image and Haraka installation + reintroduce the Haraka wrapper script
remove obsolete logfile configuration
detach containers when run via make
initial onbuild version
use environment variable to declare Haraka version in Dockerfile
use flexible entrypoint script according to docker #bestpractices
order Dockerfile instructions to make better use of cache
remove even more bashism
implement help function for entrypoint script
explicitly declare image tag in example and onbuild Dockerfile
explain setup and usage of image better