Helix is a framework for roleplay gamemodes in Garry's Mod, based off of NutScript 1.1. Helix provides a stable, feature-filled, open-source, and DRM-free base so you can focus more on the things you want: making gameplay.
To start working on your gamemode, you'll need to set up a schema for Helix. This is a specially structured gamemode that uses Helix as its base - but instead of creating all the files and bootstrapping properly yourself, you can fork/copy the skeleton schema that has all of this done already at https://github.com/NebulousCloud/helix-skeleton. The skeleton contains all the important elements you need to have a functioning schema so you can get coding right away.
Up-to-date documentation can be found at https://nebulouscloud.github.io/helix/. This is automatically updated when commits are pushed to the master branch. As it currently stands, you might find it a bit lacking. However, this will definitely improve over time as we continue polishing off the framework.
We use LDoc to build our documentation. The easiest way to start building is through LuaRocks.
luarocks install ldoc
ldoc .
You may not see the syntax highlighting work on your local copy - you'll need to copy the files in docs/js and docs/css over into the docs/html folder after it's done building.
Feel free to submit a pull request with any fixes/changes that you might find beneficial. Currently, there are no solid contributing guidelines other than keeping your code consistent with the rest of the framework.