func legacyAddHours(t time.Time, n int) time.Time {
	return time.Date(t.Year(), t.Month(), t.Day(), t.Hour()+n, t.Minute(), t.Second(), t.Nanosecond(), t.Location())
}
legacyAddHours is preserved from the old rotation calculation code to migrate from version 1 to 2.
It simply reinterprets the date with the number of hours added to the clock time.
package rotationmanager
import (
	"time"
	"github.com/target/goalert/schedule/rotation"
)