RagePresence is a ScriptHookV mod that adds support for Discord Rich Presence into Grand Theft Auto V. It shows your current mission (if playing on one), location (with a big picture) and vehicle model with make logo (if any).
Drag and drop all of the files inside of the 7z to the root of your game directory.
After installing the Mod, you will see the Rich Presence information on Discord as long as you didn't had an application sending Rich Presence information before starting the game.