Shots are neither firing automatically nor with the if condition of fire button

Question

I was trying to learn unity by following space shooter tutorial. All was good until I tried to test my game to shoot lasers. I followed everything but shots are not firing with fire button. And when I removed the if condition to get continuous shots, it's not happening also. Here's my player controller script:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[System.Serializable]
public class Boundary{
    public float xMin,xMax,zMin,zMax;

}
public class PlayerController : MonoBehaviour {

    public float speed;
    private Rigidbody player;
    public Boundary boundary;
    public float tilt,fireRate;
    public GameObject shot;
    private float nextFire;
    public Transform showSpawn;
    void Start(){
        player = GetComponent<Rigidbody>();
    }

    void update(){  
        //if (Input.GetButton ("Fire1") && Time.time > nextFire) {
            //nextFire = Time.time + fireRate;
            Instantiate (shot,showSpawn.position,showSpawn.rotation);
            //}

    }
    void FixedUpdate(){
        float moveHorizontal = Input.GetAxis ("Horizontal");
        float moveVertical = Input.GetAxis ("Vertical");

        Vector3 movement = new Vector3 (moveHorizontal,0.0f,moveVertical);
        player.velocity = movement * speed;
        player.position = new Vector3 (
            Mathf.Clamp(player.position.x,boundary.xMin,boundary.xMax),
            0.0f,
            Mathf.Clamp(player.position.z,boundary.zMin,boundary.zMax)
        );
        player.rotation = Quaternion.Euler(0.0f,0.0f,player.velocity.x*-tilt);
    }
}

And here's mover script

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Mover : MonoBehaviour {

    public float speed;
    private Rigidbody bolt;
    // Use this for initialization
    void Start () {
        bolt = GetComponent<Rigidbody>();
        bolt.velocity = transform.forward * speed;
    }

}

Here's the direct link to the part of tutorial

P.S I'm using Unity 5