Impressionist gem returning zero, why?

Question

Whats wrong with my code? Here's the index

<%= post.impressionist_count(:filter=>:ip_address) %>

Here's the controller

impressionist actions: [:show], unique: [:session_hash]
  is_impressionable :counter_cache => true, :column_name => :my_column_name, :unique => true

Here's the post.rb

is_impressionable :counter_cache => true, :column_name => :my_column_name, :unique => true