establish database tables
create association has_and_belongs_to_many between doctor and patient in doctor class
create association has_and_belongs_to_many between doctor and patient in patient class
add create_doctor method to UI
add create_patient method to UI
create list method in doctor class
add name length validation to doctor class
add name length validation to patient class
add downcase_name method to doctor class
add downcase_name method to patient class
;
;
refactors to allow doctor/and patients to relate through appointments
create create_appointment method in UI
add columns to appointments table
add view_appts method in UI
drop doctors_patients table-