Required: { name: (string), email: (string), username: (string), password: (string), role_id: (integer 1=user, 2=instructor, 3=admin) }
Required: { username: (string), password: (string) }
Required: { class_name: (string), class_type: (string), class_date: (string), class_start_time: (string), class_duration: (string), class_intensity: (string), class_location: (string), registered_participants: (integer), class_max_participants: (integer) }
Required: same as creating a class