TurboRedis is contained in a single file that can be downloaded from the GitHub project page (turboredis.lua). Just stick it somewhere that it’s accessible to LuaJIT and you’re good to go.
There is no ‘stable release’ yet. But grabbing the current one from the master branch usually works fine.
You can also clone the git repo:
$ git clone https://github.com/enotodden/turboredis.git