Adding docker-compose and alpine based Dockerfile

[niwo]

Adding docker-compose and alpine based image which separates the app from the database

[linuxbandit]

Looks great! thanks for this. I was going to do the same then I realised someone may have already, thankfully there was you.

Only feedback: I would avoid being root (on line 9 of the Dockerfile)

[J0WI]

The *-dev dependencies can be removed afterwards.
Adding libc6-compat is an anti pattern on Alpine Linux. Binaries should be build with musl-libc.
An example can be found here: https://github.com/docker-library/redmine/blob/master/Dockerfile-alpine.template