Add some related topics

Author: leereilly

topics/game-jam/index.md

@@ -2,7 +2,7 @@
 topic: game-jam
 aliases: gamejam
 display_name: Game Jam
-related: hackathon
+related: hackathon, ludum-dare, global-game-jam, game-off, js13k
 short_description: A game jam is a hackathon for creating video games.
 wikipedia_url: https://en.wikipedia.org/wiki/Game_jam
 ---