Commit 3

Added the Student class implementation
Added testing for the mentioned classes in program class
fixed bug in Major class, when dropping student from major it show negative number for student count
fixed bug in DBConnect class where the DateTime was not enabled before
fixed get_user_id function in User class, now it uses user_name and password to get the user_id
fixed get_user_id function call in Staff class to work with the changes in User class
add the call for studnet class in Object_initialization class