Symfony Doctrine ManyToOne association migration No reaction - php

Question

I have two tables one is entry.php and user.php
I Want to associate $balance of user with the $balance of entry
but when I try php bin/console doctrine:migrations:diff
I get
No changes detected in your mapping information.
this is my user.php
<?php
namespace BankBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Validator\Constraints as Assert;
/**
* #ORM\Table(name="user")
*
* #ORM\Entity(repositoryClass="BankBundle\Entity\user")
**/
class user
{
/**
* #ORM\Id
* #ORM\Column(name="id",type="integer")
* #ORM\GeneratedValue
*/
private $id;
/**
* #ORM\OneToMany(targetEntity="entry", mappedBy="balance")
* #var entry[] An ArrayCollection of entry objects.
*/
private $balance;
public function getId()
{
return $this->id;
}
public function getBalance()
{
return $this->balance;
}
}
and my entry.php
<?php
namespace BankBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Validator\Constraints as Assert;
/**
* #ORM\Table(name="entry")
*
* #ORM\Entity(repositoryClass="BankBundle\Repository\BankRepository")
**/
class entry
{
/**
* #ORM\Id
* #ORM\Column(name="id",type="integer")
* #ORM\GeneratedValue
*/
private $id;
/**
* #ORM\Column(name="amount",type="integer")
*/
private $amount;
/**
* #ORM\Column(name="balance",type="integer")
* #ORM\ManyToOne(targetEntity="user", inversedBy="balance")
*/
private $balance;
/**
* #ORM\Column(name="created_at",type="datetime")
*/
private $created_at;
}