The documentation should specify the required jsdom version

[erdeszt]

I did as a documentation said and installed the latest jsdom npm package(v11.0.0) but I've got an error when running the tests: TypeError: jsdom.createVirtualConsole is not a function. I had to downgrade to v9.0.0 to make the tests run.

The documentation should specify the version of jsdom that the app relies on(and it probably should be updated I guess). If you are ok with adding @9.0.0 to the documentation I can do a quick PR.