Redmine

Hello everyone,
I hope this is the right place for my question.

So, I run a turnkey redmine 5.1.2.stable, and I managed to install a redmine_xapian 3.0.7
Everything seems to be working fine. The indexing of the database seems to have worked too, there are no errors as far as I can tell.

Problem: when I do a search on the contents of a markdown file attached to a wiki page for example, it will not give me any results.

The documentation says something about editing the ruby script, but to honest I wouldn't know what to put in there and I'm not sure if that would even solve the issue.
This is the documentation: https://github.com/xelkano/redmine_xapian

Can anybody help me here? Am I missing something? Or am I understanding the description of the plugin wrong and it does not search attachments?

Appreciate your help.
Thanks,
khalid