Revert "disable comments"

This reverts commit cdc7ff9.

Revert while not deployable.

Author: timoschilling

config/initializers/active_admin.rb

@@ -80,19 +80,6 @@
   # Default:
   # config.root_to = 'dashboard#index'
 
-  # == Admin Comments
-  #
-  # This allows your users to comment on any resource registered with Active Admin.
-  #
-  # You can completely disable comments:
-  config.allow_comments = false
-  #
-  # You can disable the menu item for the comments index page:
-  # config.show_comments_in_menu = false
-  #
-  # You can change the name under which comments are registered:
-  # config.comments_registration_name = 'AdminComment'
-
   # == Batch Actions
   # Enable and disable Batch Actions
   config.batch_actions = false