add /management/auditors (untested)

src/timestamp.ml

@@ -67,3 +67,13 @@ let caqti : Ptime.t option Caqti_type.t =
   let encode v = Ok (encode_int64 v) in
   let decode v = Ok (decode_int64 v) in
   Caqti_type.custom ~encode ~decode Caqti_type.int64
+
+let compare a b =
+  match (a, b) with
+  | None, None -> Some 0
+  | None, _ | _, None -> None
+  | Some a, Some b ->
+      let a = ptime_to_int64 a in
+      let b = ptime_to_int64 b in
+      let c = Int64.compare a b in
+      Some c