I have a Post model that looks like this:

```
#  id         :integer         
#  author_id  :integer         
#  owner_id   :integer         
#  owner_type :string(255)
#  content    :text    

class Post < ActiveRecord::Base
  belongs_to :author, class_name: 'User'
  belongs_to :owner, polymorphic: true
end

```

The owner can be a User, Group, or a Place. I'm wondering what is the best approach to model a Comment. Considering that it shares most of its attributes with Post, I thought that the same Post model could serve as Comment using a relation like:

```
has_many :comments, class_name: 'Post', :as => :owner

```

But indeed I'm not happy at all with this solution since Post uses the same relation for storing its owner.

It's better to create a different model for comment? What about STI?