Added core game design link

src/index.md

@@ -14,11 +14,13 @@ If you would like to make contributions to this documentation site, it's hosted
 
 - [:question: How do I code?](en/general-development/setup/howdoicode.md)
 - [:package: Setting up the Dev Environment](en/general-development/setup/setting-up-a-development-environment.md)
+- [:page_with_curl: Core Game Design](en/space-station-14/core-design.md)
 - [:world_map: Mapping](en/space-station-14/mapping.md)
 - [:chart_with_upwards_trend: Git for the SS14 Developer](en/general-development/setup/git-for-the-ss14-developer.md)
 
+
 ### What should I work on?
 
 * Talk to current developers in Discord.
 * Check [the list of issues](https://github.com/space-wizards/space-station-14/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc) for anything you can work on.
-* Reading through [Acronyms & Common Nomenclature](en/general-development/codebase-info/acronyms-and-nomenclature.md) as well as the other articles on this wiki in `Tips` or `Setup` will likely help you understand what is happening.
+* Reading through [Acronyms & Common Nomenclature](en/general-development/codebase-info/acronyms-and-nomenclature.md) as well as the other articles on this wiki in `Tips` or `Setup` will likely help you understand what is happening.