Create MyTactics.v

(** 
  This file contains tactics for working with the nat-indexed family Fin, where
    --  Inductive Fin : nat -> Set :=
      ---| fz : forall n, Fin (S n)
      ---| fs : forall n, Fin n -> Fin (S n).

 Main tactic: FSimpl -- the main tactic for arithmetic on Fin
*)