title: Django hide field when creating new object
body: <p>I want to hide field name when user is creating new object, but it must be visible if user wants to edit this object. 
  I tried exclude method but it makes field invisible when i try to edit this field. for example i want to hide status field.</p>
  
  <pre><code>class Toys(BaseModel):
      name = models.CharField(max_length=255)
      tags = models.ManyToManyField(Tag, related_name='Item_tags')
      price = models.CharField(max_length=255)
      status = models.BooleanField(default=False)
  </code></pre>