Add test cases for initializing item
Add code for initializing item
Add test cases for getter methods for item
Add code for getter methods for item
Add test cases and then code for simple set methods for item
Add test cases for initializing with invalid inputs
Add code for handling initializing with invalid inputs
Add test code for seting item with invalid inputs
Add test case for initializing category object
Add code for initializing category object
Add test code for initializing category object with a list of items
Add code for initializing category object with a list of items
Add class diagram to Documents
Milestone 3
Fix conflicts