Current state of zinc makes docker container exit with segfault

[t-ionut]

From running docker-compose up the zinc container logs look like this:

2016/10/21 09:54:19 Waiting for host: tcp://redis:6379
2016/10/21 09:54:19 Connected to tcp://redis:6379
Performing system checks...

2016/10/21 09:54:24 Command exited with error: signal: segmentation fault (core dumped)

and the docker-compose logs give an extra message:

zinc_zinc_1 exited with code 255

[t-ionut]

Will stick with docker image python:3.5-alpine instead of python:3.6-alpine as it seems to work with this one