slug_django.py

def save(self, *args, **kwargs):
        if not self.id:
            max_length = Skill._meta.get_field('slug').max_length
            self.slug = orig = slugify(self.title)[:max_length]

            for x in itertools.count(1):
                if not Skill.objects.filter(slug=self.slug).exists():
                    break
                # Truncate the original slug dynamically. Minus 1 for the hyphen.
                self.slug = "%s-%d" % (orig[:max_length - len(str(x)) - 1], x)
        super(Skill, self).save(*args, **kwargs)