I agree with you that it would be best to keep the amount of required dependencies minimal. However, I also like the idea of supporting multiple formats. I myself only use Markdown for the majority of my pages but I saw at least one user posting in a past issue that was asking for RDoc support.

I also envision situations where users clone the wiki and edit it locally with a different format other than markdown then run into problems once they push it back up and attempt to view it.

Maybe we could make this configurable and add a guide for enabling whichever formats you prefer. Markdown could be the only one enabled by default, but more formats could be enabled through the `gitlab.yml` configuration file. There could also be a note next to the different formats specifying which gem must be installed on the system when you enable it.

There could be a check when the page loads to verify that the particular format of the page is enabled in the gitlab config file. If not, it could redirect the user to instructions on how to enable their preferred brand of documentation format.