Hi there,
I suggest you to keep training on different issues of OpenWISP to improve your understanding of the system.
In the meanwhile you can start working on the elastic search PR: take the work which was done previously, rebase it on the current master, fix the failing test and make it work. Most of the work was done, but there was one failing test which was never understood why it was failing, so if you can update the code to make it work on the latest master and find out what's wrong with it that's surely a plus sign for me.
I will keep looking for possible training ideas and let you know.
Best regards
Federico Capoano