Space Shooter Asteroids Not Being Destroyed

I downloaded unity 5 and completed Roll a Ball tutorial,Then I started the Space Shooter project,Everything went fine until step 9-Creating Hazards. I made the asteroid and written the scripts according to the video tutorial and it was tumbling fine but isn't being destroyed. when I shoot the laser,the laser get pasts it and nothing happens to the laser and asteroid. Help Me!

These are the scripts:

DESTROY BY CONTACT:

 using UnityEngine;
 using System.Collections;
 
 public class DestroyByContact : MonoBehaviour
 {
     void onTriggerEnter(Collider other) {
         if (other.tag == "Boundary") 
         {
             return;
         }
         Destroy(other.gameObject);
         Destroy(gameObject);
     }
 }
 

MOVER:

 using UnityEngine;
 using System.Collections;
 
 public class Mover : MonoBehaviour 
 {
     public float speed;
 
     void Start ()
     {
         GetComponent<Rigidbody>().velocity = transform.forward * speed;
     }
 }
 

PLAYER CONTROLLER:

 using UnityEngine;
 using System.Collections;
 
 [System.Serializable]
 public class Boundary
 {
     public float xMin, xMax, zMin, zMax;
 }
 
 public class PlayerController : MonoBehaviour 
 {
     public float speed;
     public float tilt;
     public Boundary boundary;
 
     public GameObject shot;
     public Transform shotSpawn;
     public float fireRate;
 
     private float nextFire;
 
     void Update ()
     {
         
         if (Input.GetButton("Fire1") && Time.time > nextFire)
         {
             nextFire = Time.time + fireRate;
 //            GameObject clone = 
             Instantiate(shot, shotSpawn.position, shotSpawn.rotation); //as GameObject;
         }
     }
     void FixedUpdate ()
     {
         float moveHorizontal = Input.GetAxis ("Horizontal");
         float moveVertical = Input.GetAxis ("Vertical");
         
         Vector3 movement = new Vector3 (moveHorizontal, 0.0f, moveVertical);
         GetComponent<Rigidbody>().velocity = movement * speed;
         
         GetComponent<Rigidbody>().position = new Vector3 
             (
                 Mathf.Clamp (GetComponent<Rigidbody>().position.x, boundary.xMin, boundary.xMax),
                 0.0f,
                 Mathf.Clamp (GetComponent<Rigidbody>().position.z, boundary.zMin, boundary.zMax)
                 );
         
         GetComponent<Rigidbody>().rotation = Quaternion.Euler (0.0f, 0.0f, GetComponent<Rigidbody>().velocity.x * -tilt);
     }
 }
 

RANDOM ROTATOR:

 using UnityEngine;
 using System.Collections;
 
 public class RandomRotator : MonoBehaviour
 {
     public float tumble;
 
     void Start ()
     {
         GetComponent<Rigidbody>().angularVelocity = Random.insideUnitSphere * tumble;
     }
 }
 

DESTROY BY BOUNDARY:

 using UnityEngine;
 using System.Collections;
 
 public class DestroyByBoundary : MonoBehaviour
 {
     void OnTriggerExit(Collider other) {
         Destroy(other.gameObject);
     }
 }
 

I am not getting any errors and I'm using Unity 5.