title: Cannot change column 'id': used in a foreign key constraint of table error on Django
body: <p>I'm trying to create models taking a MySQL database as reference using Django, but when I try to migrate, it throws me the following error:</p>
  
  <pre><code>Cannot change column 'id': used in a foreign key constraint 'fk_post' of table 'demoniosmv.images'"
  </code></pre>
  
  <p>My models look like this:</p>
  
  <pre><code>from django.db import models
  from django.contrib.auth.models import User
  from django.utils import timezone
  
  class Images(models.Model):
      #id = models.IntegerField(primary_key=True)
      fk_post = models.ForeignKey('Post', related_name="images", blank=True, null=True, on_delete = models.CASCADE)
      img_url = models.CharField(max_length=100, blank=True, null=True)
  
      class Meta:
          managed = True
  
  
  class Post(models.Model):
      #id = models.IntegerField(primary_key=True)
      author = models.ForeignKey(User, related_name="posts", on_delete = models.CASCADE)
      title = models.CharField(max_length=200, blank=True, null=True)
      text = models.TextField(blank=True, null=True)
      created_date = models.DateTimeField(default = timezone.now)
  
      class Meta:
          managed = True
  </code></pre>
  
  <p>And the SQL script from which I'm creating the database is this:</p>
  
  <pre><code>-- MySQL Script generated by MySQL Workbench
  -- Sun Jul 21 14:14:44 2019
  -- Model: New Model    Version: 1.0
  -- MySQL Workbench Forward Engineering
  
  SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
  SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;
  SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION';
  
  -- -----------------------------------------------------
  -- Schema demoniosmv
  -- -----------------------------------------------------
  
  -- -----------------------------------------------------
  -- Schema demoniosmv
  -- -----------------------------------------------------
  CREATE SCHEMA IF NOT EXISTS `demoniosmv` DEFAULT CHARACTER SET utf8 ;
  USE `demoniosmv` ;
  
  -- -----------------------------------------------------
  -- Table `demoniosmv`.`post`
  -- -----------------------------------------------------
  CREATE TABLE IF NOT EXISTS `demoniosmv`.`post` (
    `id` INT NOT NULL,
    `title` VARCHAR(200) NULL,
    `text` TEXT(1000) NULL,
    `created_date` DATETIME NULL,
    PRIMARY KEY (`id`))
  ENGINE = InnoDB;
  
  
  -- -----------------------------------------------------
  -- Table `demoniosmv`.`images`
  -- -----------------------------------------------------
  CREATE TABLE IF NOT EXISTS `demoniosmv`.`images` (
    `id` INT NOT NULL,
    `fk_post` INT NULL,
    `img_url` VARCHAR(100) NULL,
    PRIMARY KEY (`id`),
    INDEX `fk_post_idx` (`fk_post` ASC) VISIBLE,
    CONSTRAINT `fk_post`
      FOREIGN KEY (`fk_post`)
      REFERENCES `demoniosmv`.`post` (`id`)
      ON DELETE CASCADE
      ON UPDATE NO ACTION)
  ENGINE = InnoDB;
  
  
  SET SQL_MODE=@OLD_SQL_MODE;
  SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
  SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;
  </code></pre>
  
  <p>For creating the models I used the <code>insepctdb</code> command, I'm using <code>sqlclient</code> for the MySQL connection, and I'm using Django 2.2.3 with Python 3.7.</p>