moebooru/db/migrate/008_upgrade_forums.rb

class UpgradeForums < ActiveRecord::Migration[5.1]
  def self.up
    execute "ALTER TABLE forum_posts ADD COLUMN reply_count INTEGER NOT NULL DEFAULT 0"
    execute "ALTER TABLE forum_posts ADD COLUMN last_updated_by INTEGER REFERENCES users ON DELETE SET NULL"
    execute "ALTER TABLE forum_posts ADD COLUMN is_sticky BOOLEAN NOT NULL DEFAULT FALSE"
    execute "ALTER TABLE users ADD COLUMN last_seen_forum_post_id INTEGER REFERENCES forum_posts ON DELETE SET NULL"
  end

  def self.down
    execute "ALTER TABLE forum_posts DROP COLUMN reply_count"
    execute "ALTER TABLE forum_posts DROP COLUMN last_updated_by"
    execute "ALTER TABLE forum_posts DROP COLUMN is_sticky"
    execute "ALTER TABLE users DROP COLUMN last_seen_forum_post_id"
  end
end