Note that there are two occurrences of Employee, joined together.
  - Employee e: An Employee, in the role of someone who has a boss.
  
- Employee b: An Employee, in the role of
  someone who is a boss.
  
- e.name = 'Dwight Schrute': Find the Employee, e, whose name is 
      Dwight Schrute.
  
- e.boss_id = b.emp_id: e.boss_id is an employee
      id. b.emp_id is the id of a boss. This joins the two kinds of
      Employee together, (through the foreign key).
  
- b.name: The name of the boss.