I have a LXC container on my Debian system. I want to setup a public Git server on it so that it's accessible to other people. How can I do this?
Give this Howto a look. It's a little dated but should have the general steps you need to setup a Git server. The howto is titled: How To Install A Public Git Repository On A Debian Server.
Adding additional Repos + Users
To add more repos simply repeat steps #7 - #9. To add users just create Unix accounts for each additional user.