Django tags not saved for model

[sup...@rewardz.sg]

I'm trying to add tags to my reward model from my admin but after clicking save, the tags disappear and aren't saved.

Reward models.py

from taggit.managers import TaggableManager

class Reward(models.Model):

tags = TaggableManager()

Using Django 1.4.5

I've tried the other way round of creating tags from the manager in the admin and adding reward objects to it but they don't show up either.

Anyone can help me figure this out.

Thanks