Fixed some broken links

docs/on_boarding.md

@@ -4,11 +4,11 @@ Welcome to MEDLab! The purpose of this page is to help you get set up in all our
 
 MEDLab is a dynamic community, and there is no one-size-fits-all way to be involved. The best way to find your place in MEDLab is to come to weekly meetings, discuss your work with the director, and get involved in at least one of our projects.
 
-If you're looking for the more intellectual side of on-boarding, check out our [background readings](https://handbook.medlab.host/background_reading "background_reading").
+If you're looking for the more intellectual side of on-boarding, check out our [background readings](background_reading.md).
 
 ## Collaboration tools
 
-First, you'll need to get plugged into our self-managed collaboration tools. Learn more about our tools on the [Technology](https://handbook.medlab.host/technology "technology") page.
+First, you'll need to get plugged into our self-managed collaboration tools. Learn more about our tools on the [Technology](technology.md) page.
 
 -   Nathan needs to send you an invitation to create an account through Cloudron at `my.medlab.host`. This is your main account, which grants access to all the other tools.
     
@@ -59,7 +59,13 @@ Joining the MEDLab Space:
 -   Ask Nathan to invite you to the [MEDLab Space](https://cloud.medlab.host/apps/riotchat/#/room/!ODXsCLxXpycGkFBclI:medlab.host "https://cloud.medlab.host/apps/riotchat/#/room/!ODXsCLxXpycGkFBclI:medlab.host"), which will give you access to all our rooms.
     
 -   Choose which rooms you want to join by pressing the compass button right under your name in the top-left of the web interface. Be sure you're in #general, as well as the rooms related to any projects you're part of or interested in.
-    
+
+### Git
+
+Gitea is an open-source, relatively simple implementation of the Git version-control system. It is similar to the commerical platforms GitHub and GitLab but easier to self-host and manage. We use it to manage the lab's software projects and other documentation (such as this Handbook). It is a useful way to collaborate on things that are too complex for the office tools on Nextcloud.
+
+If you're a MEDLab member, you can join the [MEDLab Contributors](https://git.medlab.host/org/MEDLab/teams/medlab_contributors) team, which gives you edit access to the main MEDLab repositories. If you need this access, let Nathan know.
+
 
 ## Website profile