Can't run codecept docs locally. #752

What are you trying to achieve?

I'm trying to run codecept docs locally so I can add info about Dockerized tests environment that I'm working on with #747

What do you get instead?

When I run mkdocs I get following error:

ERROR   -  Config value: 'theme_dir'. Error: The path layout doesn't exist

If I remove theme_dir: layout form mkdocs.yml and use default theme everything works OK. I actually wasn't able to find layout directory in codecept repository so it's probably more of a question than issue - how (and if) can I run docs locally with production-like layout? :D

I can update docs without theme but it would be very nice if I could see my real changes before pushing to PR :)