Add Choose-Your-Own-Adventure git-undo guide

dont-panic-gitting-unlost/README.md

@@ -9,4 +9,4 @@ current state, and some other tricks for getting back to a sane environment.
 
 Offsite folks can join us via [BlueJeans](https://bluejeans.com/309751285).
 
-
+[next](undoing-fixing-removing.md)

dont-panic-gitting-unlost/undoing-fixing-removing.md

+# Feb 23: Don't Panic -- Gitting Unlost
+
+## Undoing, Fixing, or Removing commits
+
+Seth Robertson's excellent "Choose your own adventure"-style tutorial for 
+unwinding mistakes in git: https://sethrobertson.github.io/GitFixUm/fixup.html