Dockerfile for Blin automation

[kawaii]

Adds a very rough draft Dockerfile and .dockerignore so that we can start automating testing the module ecosystem with Blin. It accepts three environment variables currently which are $RAKUDO_OLD, $RAKUDO_NEW and $MODULES. The first two will default to 2018.10 and HEAD respectively if you do not provide them. $MODULES should be a space-separated list of modules (example below), if left blank it should simply test the entire ecosystem. Be warned.

Example:

docker build -t perl6/blin:latest $PWD
docker container run -e MODULES="DBIish URI::Encode" perl6/blin:latest

[AlexDaniel]

Is there any way to pull all files from the output/ directory? I'm not happy with the cat workaround.

[kawaii]

@AlexDaniel yes, users can be directed to use a bind-mounted Docker volume like so:

docker container run -e MODULES="DBIish URI::Encode" \
                       -v /tmp/blin-output:/opt/perl6/blin/output:rw \
                       perl6/blin:latest

Which then deposits the output files into my /tmp/blin-output:

# kane @ shuppet in /tmp/blin-output [17:52:15] 
$ ll
total 52K
-rw-r--r-- 1 root root 45K Mar 15 17:52 data.json
-rw-r--r-- 1 root root  77 Mar 15 17:52 overview

Does this satisfy your requirement if part of the documentation? Of course, we still need to figure out the issues we discovered in IRC first before this sees any production use anyway. :slightly_smiling_face:

[AlexDaniel]

I guess you can merge this? I can't tell if it's useful already.

[kawaii]

@AlexDaniel I don't appear to have write access to this repository, I pushed some minor updates to the PR branch though just to update it a little bit. It's not super useful currently but if Blin automation is on our to-do list then it goes some way to helping towards that goal.

[AlexDaniel]

@kawaii can you try now?