[1.5pt] Create Source class with an association to the Item class - Student D

[misalazeem]

• Create Source class with an association to the Item class (in a separate .rb file).

• All Source class properties visible in the diagram should be defined and set up in the constructor method.

• add_item method in the Source class

  • should take an instance of the Item class as an input
    

  • should add the input item to the collection of items
    

  • should add self as a property of the item object (by using the correct setter from the item object)