class AddPraisesCountToLibraries < ActiveRecord::Migration[5.2]
  def change
    add_column :libraries, :praises_count, :integer, :default => 0

    Library.find_each do |library|
      praises_count = library.praise_treads.count
      library.update_column(:praises_count, praises_count)
    end
  end
end