2d Character won't jump

I am current going through Microsoft Virtual Academy and I have come across one of their scripts which won't let me jump. I assume it is because of the changes from Unity 4 to 5(Unity updated this script for me), but I can't figure it out.

I added the statement if(Input.GetButtonDown("Fire1")) {} as it seemed to be missing from the downloaded script but I cannot figure what else could be wrong.

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;

 //This script makes the character move when the screen is pressed and handles the jump
 public class CharacterFinal : MonoBehaviour
 {
 public bool jump = false;        // Condition for whether the player should jump.    
 public float jumpForce = 10.0f;        // Amount of force added when the player jumps.
 private bool grounded = false;        // Whether or not the player is grounded.
 public int movementSpeed = 10;        // The vertical speed of the movement
 private Animator anim;            // The animator that controls the characters animations

 void Awake()
 {
     anim = GetComponent<Animator>();
 }
 

 //This method is called when the character collides with a collider (could be a platform).
 void OnCollisionEnter2D(Collision2D hit)
 {
     grounded = true;

 }

 //The update method is called many times per seconds
 public void Jump()
 {
     if (Input.GetButtonDown("Fire1")) {
         // If the jump button is pressed and the player is grounded and the character is running forward then the player should jump.
         if (grounded == true) {
             jump = true;
             grounded = false;
             //We trigger the Jump animation state
             anim.SetTrigger ("Jump");
         }
     
     }

 }

 public void Slide()
 {
     if(grounded == true)                        
     {
         //slide = true;
         //We trigger the Jump animation state
         anim.SetTrigger("slide");
     }

 } 




 //Since we are using physics for movement, we use the FixedUpdate method
 void FixedUpdate ()
 {

     //if died that 
     GetComponent<Rigidbody2D>().velocity = new Vector2(movementSpeed, GetComponent<Rigidbody2D>().velocity.y );
     //else
     //moving
 
     
     // If jump is set to true we add a quick force impulse for the jump
     if(jump == true)
     {
         // Add a vertical force to the player.
         GetComponent<Rigidbody2D>().AddForce(new Vector2(0f, jumpForce),ForceMode2D.Impulse);
         
         // We set the variable to false again to avoid adding force constantly
         jump = false;
     }
 }

}