adding elastic collisions to noc track

Author: shiffman

content/tracks/main-tracks/the-nature-of-code-2/index.json

@@ -1,5 +1,5 @@
 {
-  "title": "The Nature of Code 2",
+  "title": "The Nature of Code",
   "date": "2020-02-15",
   "playlistId": "PLRqwX-V7Uu6ZV4yEcW3uDwOgGXKUUsPOM",
   "description": "Can the unpredictable evolutionary and emergent properties of nature be captured in software? Can understanding the mathematical principles behind the physical world help to create digital worlds? This learning playlist focuses on the programming strategies and techniques behind computer simulations of natural systems. I'll explore topics ranging from basic mathematics and physics concepts to more advanced simulations of complex systems. Subjects covered include physics simulation, trigonometry, self-organization, genetic algorithms, and neural networks. This track accompanies https://natureofcode.com/",
@@ -72,6 +72,7 @@
     {
       "title": "Physics Libraries",
       "videos": [
+        "challenges/184-elastic-collisions",
         "noc/6-physics-libraries/1-matterjs-introduction",
         "noc/6-physics-libraries/2-matterjs-introduction-continued",
         "noc/6-physics-libraries/3-matterjs-deleting-bodies",