Our next program is for office administrators to track patients in a doctor's office. Build out the following features that let an administrator:  Add a doctor to the system, including their name and specialty as columns. Practice using attr_reader, and hashes to initialize your objects. Add a patient to the system, including their name and birthdate. Assign a patient to a doctor. List all of the doctors in a particular specialty. A doctor can only have one specialty. (Hint: change from storing specialty as a column to giving it its own table.) Mark what insurance a doctor accepts. In this practice, each doctor only accepts one insurance company. The choices currently are Red Shield, Health Cross, and Pacific Span, but the administrators may need to add others later. (Hint: don't hard-code in these names - just create a table for insurance companies, then add these three as starters.) Update and delete doctors, patients, specialties, and insurance companies. View a chart of doctors including the number of patients they see. Use the SQL COUNT function; practice your online search skills to figure out how it works. Add an appointment, including the doctor, patient, date, and cost. Choose a doctor, input a date range, and view how much the doctor billed in that time. Use the SQL SUM function. Search for a patient by name. Again, search online to figure out how to do this.