I have made some custom fields in my user model of django,what i was trying to do is to offer the user to set his/her profile by submitting those fields.although my custom model is working fine.since I can edit or add those fields in my admin site mode.

But when I try to submit that form as a user, it gives an error like this:-

Exception Type: IntegrityError
Exception Value: UNIQUE constraint failed: blog_profile.user_id

my models.py:-

class Profile(models.Model):
    user = models.OneToOneField(User,unique=True,on_delete=models.CASCADE,default=1)
    bio = models.TextField(max_length=500,null=True,blank=True)
    location = models.CharField(max_length=30,null=True,blank=True)
    birth_date = models.DateField(null=True,blank=True)
    pic=models.FileField(default='/user.png',null=True,blank=True)


@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
    if created:
        Profile.objects.create(user=instance)

@receiver(post_save, sender=User)
def save_user_profile(sender, instance, **kwargs):
    instance.profile.save()

forms.py:-

class ProfileForm(forms.ModelForm):
    class Meta:
        model=Profile
        fields = ['bio','location','birth_date','pic']

views.py:-

def set(request):
   if request.user.is_authenticated():
        if request.method == 'POST':
            form=ProfileForm(request.POST,request.FILES)
            if form.is_valid():
                item=form.save(commit=False)
                item.pic=request.FILES['pic']
                item.save()
                return redirect('/blog')
            else:
                return HttpResponse('Invalid')
        else:
            form=ProfileForm()
            return render(request,'blog/set.html',{'form':form})

My template for set is:-

{% extends 'blog/base.html' %}
{%block body%}
<div class="container">
    <div class="row">{{hell}}
        <div class="col-md-6 col-md-offset-3">
            <div class="alert alert-success" role="alert"><strong>Well Done!</strong> {{user.username}} You Have Succesfully Registered!</div>
        </div>
    </div>
    <form method="POST" enctype="multipart/form-data">{% csrf_token %}

        {{form.as_p}}
    <input type="submit" value="Edit">
    </form>
</div>
{%endblock%}

This is my attempt please help me i am new to all of these stuffs thanks in advance.