[CentOS] Changing default file type in Centos 6

Sat Feb 27 18:38:09 UTC 2016
H <agents at meddatainc.com>

It turns out my markdown files - extension .md - are of the "Genesis 
ROM" file type in Centos 6. Googling did not turn up any obvious places 
to change this in Gnome - neither in my local directory or in /etc/gnome.

Where would I be able to change this default file type for files with 
the extension .md? I have already changed the default application to 
geany (with the markdown extension.)

Thank you.