commit bench folder (also committing examples folder but that's kind of broken at this state)

bench/transaction.sml

@@ -0,0 +1,11 @@
+signature TRANSACTION =
+sig
+  type t
+  val empty: t
+  val insert: int * string * t -> t
+  val delete: int * int * t -> t
+  val toString: t -> string
+
+  val title : string
+  val txns : (int * int * string) vector
+end