use uuid only additionally for booking

db/booking.js

@@ -5,7 +5,8 @@ import { getDays, dateFormatBackend } from '../helpers/date'
 
 const BookingSchema = new mongoose.Schema(
   {
-    _id: {
+    // need a seperate uuid to be able to target a booking anonimously
+    uuid: {
       type: String,
       default: uuidv4,
     },