title: Warning: Auto-created primary key used when not defining a primary key type, by default 'django.db.models.AutoField'
body: <p>Why this is showing a warning as it default take the primary key from the User model so should I also declare the primary key the Registration or candidate model again.
  models.py</p>
  <pre><code>from django.db import models
  from django.contrib.auth.models import User
  # Create your models here.
  
  
  class Registration(models.Model):
      fname = models.CharField(max_length=30)
      lname = models.CharField(max_length=30)
      # phone = models.BigIntegerField(max_length=10,primary_key=True)
      dob=models.DateField()
      user = models.OneToOneField(User,on_delete=models.CASCADE,primary_key=True)
      def __str__(self):
          return self.fname
  
  class candidate(models.Model):
      full_name = models.CharField(max_length=30)
      position = models.CharField(max_length=30)
      total_vote = models.IntegerField(default=0)
      def __str__(self):
          return &quot;{} -- {}&quot;.format(self.full_name,self.position)
  </code></pre>
  <p>problem occured</p>
  <pre><code>WARNINGS:
  poll.candidate: (models.W042) Auto-created primary key used when not defining a primary key type, by default 'django.db.models.AutoField'.
          HINT: Configure the DEFAULT_AUTO_FIELD setting or the PollConfig.default_auto_field attribute to point to a subclass of AutoField, e.g. 'django.db.models.BigAutoField'.
  </code></pre>