public static function saveCoach(Coach $coach)
 {
     $conn = connection::getConnectionObject();
     $con = $conn->getConnection();
     $sql = $con->prepare("INSERT INTO coach VALUES (?,?)");
     $sportid = $coach->getSportId();
     $sportname = $coach->getName();
     $sql->bind_param("ss", $sportid, $sportname);
     if ($sql->execute() == TRUE) {
         echo "New record created successfully (coach added)";
     } else {
         echo "Error in adding sport: " . $sql . "<br>";
     }
 }