Add content directories for design-system roadmap

scripts/content-skeleton.ts

@@ -49,6 +49,7 @@ const roadmaps: Record<string, RoadmapType> = {
   javascript: require('../public/project/javascript.json'),
   nodejs: require('../public/project/nodejs.json'),
   qa: require('../public/project/qa.json'),
+  'design-system': require('../public/project/design-system.json'),
 };
 
 if (!roadmapKey || !roadmaps[roadmapKey]) {