title: Django: How to automatically change a field's value at the time mentioned in the same object?
body: <p>I am working on a django project for racing event in which a table in the database has three fields.</p>
  
  <p>1)Boolean field to know whether race is active or not</p>
  
  <p>2)Race start time</p>
  
  <p>3)Race end time</p>
  
  <p>While creating an object of it,the start_time and end_time are specified. How to change the value of boolean field to True when the race starts and<br>
  to False when it ends? How to schedule these activities?</p>