link to megarepo

Author: mstksg

README.md

@@ -1,6 +1,13 @@
 Advent of Code 2021
 =====================
 
+Everything has been moved to my [Advent of Code Megarepo][megarepo]!
+
+[megarepo]: https://github.com/mstksg/advent-of-code
+
+Archived
+========
+
 <!--
 This file generated by the build script at ./Build.hs
 -->