How to create Sale for particular Item

in Development
Currently i have backend system in ruby on rails, i want to sync this system with my lightspeed backend system. when any item order from my application, How can i update the QOH of that product for particular shop ? Or Do i need to create Sale for that item ? So, it will be easy for both end.
3 comments
If it was sold, create a sale in Lightspeed. Other ways to adjust inventory are explained in this tutorial:
http://developers.lightspeedhq.com/retail/tutorials/inventory/
Lightspeed HQ
below is my API request
https://api.merchantos.com/API/Account/{account_id}/Item.json?load_relations=["ItemShops","Images","Category"]
How can i load Parent relation of Category ?
Lightspeed HQ