docker / memory leaks

[jeroen]

I added a docker script to test for memory leaks. However I don't have sufficient permission in the repo to install the hook that triggers a build on commits.

Here is example output: https://hub.docker.com/r/jeroenooms/jqr/builds/

[richfitz]

Try now - I've bumped you up to admin

[jeroen]

OK we can now see memory leak summaries by looking at dockerhub build logs. Maybe I'll try to fix some of those for a future version (CRAN doesn't seem to bother memleaks though).