Adding Items - Githubissues

Description

As a Manager, I would like to add new copies of an item in order to expand the inventory

Managers are able to see an Add Items option on their view of the website (when they are logged in as managers)
When the Manager selects the Add Items option, they are presented with a page that contains three fields: UPC, Quantity, and Price (Optional). Below the fields, the page also contains the Add button
When the Manager enters all the information the system updates the item in the database that matches the UPC provided by the Manager. The price of the item is now changed to the entered price
If the Manager enters UPC and Quantity but not the Price the system updates the item in the database that matches the UPC provided by the Manager. The price of the item stays the same
If the Manager enters all the information but the system cannot find the item in the database that matches the UPC, it creates a new item in the database and assigns it the entered UPC, Quantity and Price
If the Manager enters UPC and Quantity but not the Price but the system cannot find the item in the database that matches the UPC provided, a window prompt appears that says "This item does not yet exist in the database. If you would like to add it, please enter the Price" and OK. When the Manager clicks OK they are directed back to the Add Items page where they must populate the Price field

Verify that only Managers can see the Add Items option (i.e., the user is logged in as a Manager)
Verify that the item exists in the database
Verify that for the matching item in the database, the quantity and price has been updated according to what was entered by the Manager
Verify that if the UPC did not match any in the database and the price was provided, the new item is added to the database
Verify that if the UPC did not match any in the database and the price was not provided, an error message is generated prompting the Manager to include the price, and no item is added to the database