Assignment 2
  Using Assignment 1 as a starting point, 
  - Add behavior to appropriate classes in your class diagram.  Use the 
    Bookstore Example 2 as a guide.
 
  - Write Java code to implement the classes, variables, and relationships in 
    your class design.  Use comments as appropriate to document the intent 
    of each class.
 
  - Add behavior as methods with empty bodies (or methods returning dummy data). 
  
 
  - Compile your code. 
 
Deliverables: Turn in your updated class diagram and your compilable code.