Install Gollum

gem install gollum

Clone your wiki

git clone https://lab.civicrm.org/community/sustainability.wiki.git
cd sustainability.wiki

Start Gollum and edit locally

gollum
== Sinatra/1.3.5 has taken the stage on 4567 for development with backup from Thin
>> Thin web server (v1.5.0 codename Knife)
>> Maximum connections set to 1024
>> Listening on 0.0.0.0:4567, CTRL+C to stop