title: Auto-create primary key used when not defining a primary key type warning in Django
body: <p>I just updated my python from 3.9.1 to 3.9.4. When I tried to run the server. The console gave me a warning for this:</p>
  <pre><code>WARNINGS:
  learning_logs.Entry: (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 LearningLogsConfig.default_auto_field attribute to point to a subclass of AutoField, e.g. 'django.db.models.BigAutoField'.
  learning_logs.Topic: (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 LearningLogsConfig.default_auto_field attribute to point to a subclass of AutoField, e.g. 'django.db.models.BigAutoField'.
  No changes detected in app 'learning_logs'
  </code></pre>
  <p>May I please know how do I fix this.
  I read the documentation about this, but I don't understand how this part <a href="https://docs.djangoproject.com/en/3.1/topics/db/models/" rel="noreferrer">this page</a> relates to this.</p>
  <p>Models.py</p>
  <pre><code>from django.db import models
  from django.contrib.auth.models import User
  # Create your models here.
  
  class Topic(models.Model):
      text = models.CharField(max_length = 200)
      date_added = models.DateTimeField(auto_now_add = True)
      image = models.ImageField(upload_to = 'backgroud_images', null = True, blank = True)
      owner = models.ForeignKey(User,on_delete = models.CASCADE)
      def __str__(self):
          return self.text
  
  
  
  class Entry(models.Model):
      topic = models.ForeignKey(Topic,on_delete = models.CASCADE)
      text = models.TextField()
      date_added = models.DateTimeField(auto_now_add = True)
  
      class Meta:
          verbose_name_plural = &quot;Entries&quot;
  
      def __str__(self):
          return self.text[:50]
  </code></pre>