[DO NOT DEPLOY] Add extension sargedev/elo

Fixes #172

Author: UnsignedArduino

content/extensions/076-sargedev---elo.md

@@ -0,0 +1,8 @@
+---
+repo: "https://github.com/sargedev/elo"
+links:
+  - title: Forum post
+    url: "https://forum.makecode.com/t/extension-elo-ratings/24574?u=unsignedarduino"
+---
+
+The Elo rating system, most known for its use in chess, is a method used to estimate the relative strength between players in a zero-sum game. The singular block can be used after a "win" or "loss" to calculate the correct change to the player's elo. Adds a category to the toolbox called `Elo`.