The test for CI was added by accident. This patch removes it again and
fixes the build error.

In order to make it easier to discover, mentioning the exposed port in 
the Dockerfile will make it easier to set things up.

It seems like local_addr is not in release 2.0.1 which causes errors 
with the finished image. Commenting it should solve that problem.

Bash is not provided by default on alpine linux. The script is not using 
any bash specific features, which meakes it easy to replace it with ash.

In order to minimize the attack surface and to keep the image size 
small, using alpine linux should be the better choice.

This patch switches to an alpine base image with minimal dependences for 
building the golang application.

Version numbers for this project start with a `v`.