demo_app/my_platform/db/migrate/20161011140942_add_taggings_counter_cache_to_tags.your_platform.rb
# This migration comes from your_platform (originally 20161011140815)
# This migration comes from acts_as_taggable_on_engine (originally 3)
class AddTaggingsCounterCacheToTags < ActiveRecord::Migration[4.2]
def self.up
add_column :tags, :taggings_count, :integer, default: 0
ActsAsTaggableOn::Tag.reset_column_information
ActsAsTaggableOn::Tag.find_each do |tag|
ActsAsTaggableOn::Tag.reset_counters(tag.id, :taggings)
end
end
def self.down
remove_column :tags, :taggings_count
end
end