Er model.... Entity relationship diagram about how patient sets appointment to a doctor for check up....?
```+----------------+
| Patient |
+----------------+
| - patient_id |
| - patient_name |
| - patient_age |
| - patient_gender |
| - patient_phone |
| - patient_email |
+----------------+
+-------------------+
| Doctor |
+-------------------+
| - doctor_id |
| - doctor_name |
| - doctor_age |
| - doctor_gender |
| - doctor_phone |
| - doctor_email |
| - doctor_specialty |
+-------------------+
+-----------------------+
| Appointment |
+-----------------------+
| - appointment_id |
| - patient_id |
| - doctor_id |
| - appointment_date |
| - appointment_time |
| - appointment_status |
+-----------------------+
```