A few years ago, I wrote an article for CodeMentor.io where you learn how to create a Slack bot and search engine for your Github wiki. It was a fun project to make the wiki at work more accessible and useful and get more people to contribute and to use it as a knowledge base.
However, if I were to do it all over again, this time in 2018 and going into 2019, I would probably check out Outline.
Outline is a free/open-source wiki built with React and Node.js. While I advise against using Slack for opensource project communication, some companies have really hopped aboard the Slack-train, and may not want to switch. Most companies don’t have the greatest wiki that is searchable through a Slack bot. Outline does.
You can try it out here: https://www.getoutline.com/