Update 'README.md'

README.md

 the second Objects lab.
 
 look for the Chapter reading you need in the doc folder.
+
+Exercise 2.16 To what class does the following constructor belong?
+`public Student(String name)`
+Exercise 2.17 How many parameters does the following constructor have andwhat are their types?
+`public Book(String title, double price)`
+Exercise 2.18 Can you guess what types some of  the Bookclass’s fields mightbe? Can you assume anything about the names of its fields?