adding schedule by company

src/pages/UsersPage.tsx

@@ -76,6 +76,10 @@ export function UsersPage({ backendPreference }: UsersPageProps) {
 
   const schedulesByUser = useMemo(() => {
     return schedules.reduce<Record<number, Schedule[]>>((accumulator, schedule) => {
+      if (typeof schedule.user_id !== "number") {
+        return accumulator;
+      }
+
       accumulator[schedule.user_id] = [...(accumulator[schedule.user_id] ?? []), schedule];
       return accumulator;
     }, {});