how to add items to order

[twinkle]

Hi,

I am trying to add items to an order received by creating an order but
it says bad request.

Here is what I am using

I am using Http POST method

http://api.opendining.net/orders/{ORDER_ID}/items/{Item_Id}

but it is coming back with bad request

Note:- ORDER_ID i am using the value I got by creating an order first
Item_Id is the item from the menu

Thanks