title: Django values method - related objects in list
body: <p>Hi help with values () method of queryset. When displaying related fields (Foreign key), the data is repeated, can this data be grouped?</p>
  <pre><code>class Product(models.Model):
      category = models.ForeignKey(Category, related_name='product', on_delete=models.CASCADE)
      title = models.CharField(max_length=250)
      slug = models.SlugField(max_length=250, unique=True, db_index=True)
  
  class ProductImage(models.Model):
      product = models.ForeignKey(Product, related_name='product_image', on_delete=models.CASCADE)
      image = models.ImageField(upload_to='img/models/')
      is_main = models.BooleanField()
  </code></pre>
  <p>View code</p>
  <pre><code>data = Product.objects.all().values('pk', 'title', 'product_image')
  </code></pre>
  <p>Example here</p>
  <p>This is how it is displayed</p>
  <pre><code>[
      {'pk': 1, 'title': 'Product 1', 'product_image__image': 'img/models/mod_wpYzlnm.png'}, 
      {'pk': 2, 'title': 'Product 2', 'product_image__image': 'img/models/mod2_wEr0D2q.png'},
      {'pk': 2, 'title': 'Product 2', 'product_image__image': 'img/models/mod_pPQqmjB_we175uR.png'},
      {'pk': 10, 'title': 'Product 3', 'product_image__image': 'img/models/mod_3mTxkb9_z4lKV3l.png'}, 
      {'pk': 10, 'title': 'Product 3', 'product_image__image': 'img/models/heart.png'}
  ]
  </code></pre>
  <p>This is how it should be</p>
  <pre><code>[
      {'pk': 1, 'title': 'Product 1, 'product_image':[ 
          {'image':'img/models/mod_wpYzlnm.png'}
      ]}, 
      {'pk': 2, 'title': 'Product 2', 'product_image': [
          {'image':'img/models/mod2_wEr0D2q.png'}, 
          {'image':'img/models/mod_pPQqmjB_we175uR.png'}
      ]},
      {'pk': 10, 'title': 'Product 3',  'product_image': [
          {'image':'img/models/mod_3mTxkb9_z4lKV3l.png'}, 
          {'image':'img/models/heart.png'}
      ]}, 
  ]
  </code></pre>