Lets assume you already have 2 tables:
menu
id
menutext
and
user
userid
username
You'd then create a THIRD table
usermenuorder
userid
menuid
order
If you had 3 menu records
id 1 --- First Menu
id 2 --- Second Menu
id 3 -- Third menu
user 1 could create 3 records
userid 1
menuid 1
order 3
userid 1
menuid 2
order 1
userid 1
menuid 2
order 2
Use a sql query like this to return menus in user 1's desired order:
SELECT menutext
FROM menu
INNER JOIN usermenuorder
ON menuid=menu.id
WHERE userid=1
ORDER BY usermenuorder.order