Milestone $4$ File I$/$O Integration:

$-$ Update the Inventory Manager UML class diagram to support the following new features:

o Initialization of Store inventory from an external JSON file using the File Service.

o Proper exception handling for all File I$/$O and JSON serialization.

$-$ Update the flow chart of the logic of a Game User interacting with the Store Front and with the internal Inventory Manager and Shopping Cart.

$-$ Implement the code for all UML class designs.