Update index.md

Author: DamianQualshy

docs/index.md

@@ -25,4 +25,7 @@ You can also browse our [GitHub Organization](https://github.com/Gothic-Multipla
 
 ### Useful plugins
 ##### Lua Language Server
-- [Lua Language Server](https://marketplace.visualstudio.com/items?itemName=sumneko.lua)
+- [Lua Language Server](https://marketplace.visualstudio.com/items?itemName=sumneko.lua)
+
+##### IntelliSense for Gothic Multiplayer
+- [IntelliSense for Gothic Multiplayer](https://github.com/Gothic-Multiplayer-Classic/vscode-gothicmultiplayer)