class Product(models.Model):
    quantity = models.DecimalField( "Quantity", max_digits=8, decimal_places=2, default=0)
    retail_price = models.DecimalField( max_digits=10, decimal_places=2, default=0, blank=True)
    purchase_price= models.DecimalField( max_digits=8, decimal_places=2, default=0, blank=True)
    timi_xondrikis = models.DecimalField( max_digits=8, decimal_places=2, default=0, blank=True)

class ProductForm(ModelForm):
    class Meta:
        model = Product
        fields=('quantity','retail_price')