Add CONTRIBUTING.md

CONTRIBUTING.md

@@ -0,0 +1,35 @@
+# Contributing to raylib-zig
+
+Thank you for your interest in contributing to raylib-zig. There are some guidelines you will need to follow in order
+to get your contribution added to the project as fast as possible.
+
+## Updates to the Zig version
+
+This binding will never target any Zig version newer than the latest release. Fixes that don't affect compatibility
+with the latest release and allow the binding to be used on a pre-release/HEAD version of Zig may be accepted.
+
+## Updates to the raylib version
+
+Usually this binding will stay on the latest release commit for raylib, but occasionally upgrade to a HEAD version when
+there are changes made, critical to the Zig build. In those cases there will be a release tag on GitHub, marking the
+latest commit that uses a raylib release. Previously there were extra branches for older versions of raylib, but this
+approach was abandoned.
+
+## Updates to the binding files
+
+raylib-zig is built mostly through the `generate_functions.py` script. It creates the definitions to access the raw C
+functions, and creates aliases with proper Zig argument and return types, Zig style names and errors. The raylib types,
+however, are created manually and should only be updated in their respective preludes:
+ - `lib/preludes/raylib-prelude.zig` for raylib types
+ - `lib/preludes/raymath-prelude.zig` for raymath types
+ - `lib/preludes/rlgl-prelude.zig` for rlgl types
+ - `lib/preludes/raygui-prelude.zig` for raygui types
+
+Before any commit you make, you should always run `generate_functions.py` to ensure your changes are persistent
+throughout other updates.
+
+## Updates to the build files
+
+Updates to raylib-zig's `build.zig`, as any other contributions to binding files, are very welcome. However, when
+updating public names or APIs, you should always ensure that the project template in `project_setup.sh` still
+works with them.