Implemented TODO tasks

Some of the TODO instructions were ambiguous to me:  For example, the entries inserted into the database in DatabaseUtil.initDB() are not in the List people instance, and it wasn't clear whether they should be or not, so I implemented it both ways.

Also the last TODO instruction didn't make sense.  "insert the new person objects into the database"  The new persons were already inserted in the previous instructions, so I took that to mean to create yet another new person.

Finally, I know there should be validation on database lengths, assumptions on whether NAME is a unique key or not, whether duplicate names can be inserted, etc.  These are things I would take into consideration if I knew the requirements.