Add Dockerfile, compose, configs(ref #32)

[iamsimakov]

I tried to do Dockerfile to automate starting project. But locally I saw some errors after starting. It was Error while loading archived messages of all chats, but I can send/receive messages. In the console, there was 503 error on xmpp protocol. Could anybody debug it? And... I think entrypoint.sh looks a little ugly.. but I would like to give all these changes as a start point to this perfect project.