Make a big list of items, and each item will be ordered as zero (equal order)
Now, say you want to move one item to the bottom. No worries, make that items order number one or more, and bam - straight to the bottom it goes.
But what if you just want to move one up? Do you have to give a higher order number to all other items?
Nope.
Just use negative numbers. a -1 item is "lighter" than a 0 or 1 or 2, and therefore will "rise" in the list.
Maybe you knew this, maybe you didnt. I just figured it out and thought I should share with the class.
Have a nice day!!