How to add tags using taggit in Django admin

I am trying to add tags to my blog app using django admin but every-time I add a tag through the admin console, I get this error Can't call similar_objects with a non-instance manager

Is this because I am not saving the the tags in the admin or is this because I implemented taggit wrongly?

This is where I define my view and display and article, I try to grab similar articles using taggit

def article(request, slug):
    article = Post.objects.filter(slug=slug).values()
    article_info = {
        "articles": article,
        "related_articles" : Post.tags.similar_objects()
    }

    return render(request, 'article.htm', article_info)

Update

This is how my post model looks like

STATUS = (
    (0,"Draft"),
    (1,"Publish")
)

class Post(models.Model):
    title = models.CharField(max_length=200, unique=True)
    slug = models.SlugField(max_length=200, unique=True)
    author = models.CharField(max_length=200, unique=True)
    author_biography = models.TextField(default="N/A")
    updated_on = models.DateTimeField(auto_now= True)
    content = models.TextField()
    upload_image = models.ImageField(default="default.png", blank=True)
    created_on = models.DateTimeField(auto_now_add=True)
    status = models.IntegerField(choices=STATUS, default=0)
    tags = TaggableManager()

    class Meta:
        ordering = ['-created_on']

    def __str__(self):
        return self.title

Solution

Right, I see the problem.

You are trying to access tags on the class Post and not an instance of Post. However, you're also using filter() and values() and the variable name is singular, so I think there's perhaps a misunderstanding there as well.

I assume the kind of thing you want to do is this;

def article(request, slug):
    article = Post.objects.get(slug=slug)
    article_info = {
        "article": article,
        "related_articles" : article.tags.similar_objects()  # Instance of Post is article
    }

    return render(request, 'article.htm', article_info)