How to rotate an object to face the direction it's going?

Hello, I currently have a waypoint system but I can't seem to figure out how to make the object face the direction it's going. This is the code for my waypoint system.

 using UnityEngine;
 using System.Collections;
 
 public class Waypoints : MonoBehaviour
 {
         private Transform startMarker, endMarker;
         public Transform[] waypoint; 
         private float speed = 1.0F;
         private float startTime;
         private float journeyLength;
     //    public Transform target;
         private int currentStartPoint;
 
         void Start ()
         {
                 currentStartPoint = 0;
                 SetPoints (); //Function om de waypoints in te zetten
         }
     
         void SetPoints ()
         {
                 startMarker = waypoint [currentStartPoint];
                 endMarker = waypoint [currentStartPoint + 1];
                 startTime = Time.time;
                 journeyLength = Vector3.Distance (startMarker.position, endMarker.position);
         }
         void Update ()
         {
                 float distCovered = (Time.time - startTime) * speed; 
                 float fracJourney = distCovered / journeyLength;
                 transform.position = Vector3.Lerp (startMarker.position, endMarker.position, fracJourney);
                 if (fracJourney >= 1f && currentStartPoint + 1 < waypoint.Length) {
                         currentStartPoint++;
                         SetPoints ();
                 }
                 
         }
 }