Sends a tweet with the title/short_url if applicable.

def save_model(self, request, obj, form, change):
        """
        Sends a tweet with the title/short_url if applicable.
        """
        super(TweetableAdminMixin, self).save_model(request, obj, form, change)
        if Api and request.POST.get("send_tweet", False):
            auth_settings = get_auth_settings()
            obj.set_short_url()
            message = truncatechars(obj, 140 - len(obj.short_url) - 1)
            api = Api(*auth_settings)
            api.PostUpdate("%s %s" % (message, obj.short_url))