db/migrate/20161011010929_subscribe_authors_to_diary_entries.rb

   1 class SubscribeAuthorsToDiaryEntries < ActiveRecord::Migration[5.0]
   2   def up
   3     DiaryEntry.find_each do |diary_entry|
   4       diary_entry.subscriptions.create(:user => diary_entry.user) unless diary_entry.subscribers.exists?(diary_entry.user.id)
   5     end
   6   end
   7
   8   def down; end
   9 end