Github Wikis are available for public github repos or paid private github repos. As I have a free private github repo I don't have access to this feature, so I am looking if there is a way to reproduce its functionality some other way.
I am not looking for something fancy, functionality wise, just to be able to link different markdown documents.
Searching online I saw some suggestions about creating markdown documents and then hosting them on a github page, unfortunately the github pages are also not available for a free private github repo.
I haven't done this in awhile but I once had success designating a 'Docs' folder in my GitHub repo and then just maintaining my markdown files (Wiki) in there. I believe GitHub automatically renders the markdown correctly and you can even navigate (link) from page to page and display images. You'll want to designate consistent location of your images or it gets crazy - if you are using them. This should work.