ancestry gem with position sorting

Question

I use ancestry gem for create nested categories. this gem is super fast but how can i add position filed to ancestry. I want tree item sort by parent and child & position. think you create category like:

games
- football
- tennis

after a while you add another child to games like boxing

games
- football
- tennis
- boxing

but you want show boxing above the tennis like :

games
- football
- boxing
- tennis

and this was nice to be down by a drag and drop. how should i do add position to view and is it possible a simple way to drag and drop. i tried to use the gem that recommended by ancestry but it have lot of unfixed bug.