[answered] How to fix an error on my Item Collection Script?

I'm making a script to check if a ray has hit a gameobject with a certain tag, but i have encounter a problem with this error:

NullReferenceException: Object reference not set to an instance of an object ItemCollection.Update () (at Assets/Scripts/ItemCollection.cs:24)

The line where the error occurs is: if (hit.collider.gameObject.tag == "Collectable") {

     using UnityEngine;
     using System.Collections;
     
     public class ItemCollection : MonoBehaviour {
     
         public int rayLength;
         public int items = 0;
         bool gui = false;
     
         // Use this for initialization
         void Start () {
             
         }
         
         // Update is called once per frame
         void Update () {
     
             RaycastHit hit = new RaycastHit();
             Vector3 fwd = transform.TransformDirection(Vector3.forward);
     
             Debug.DrawRay (transform.position, fwd);
     
             if (Physics.Raycast (transform.position, fwd, rayLength)) {
                 if (hit.collider.gameObject.tag == "Collectable") {
                     gui = true;
                     if (Input.GetButtonDown ("Interact")) {
                         items ++;
                         Destroy(hit.collider.gameObject);
                         gui = !gui;
                     }
                 }
                 else {
                     gui = false;
                 }
             }
     
         }
     
         void OnGui() {
     
             if (gui == true) {
                 GUI.Box(new Rect(Screen.width / 2 - 150, Screen.height / 2 - 150, 100, 20), "Press 'E' to Collect");
             }
         }
     }