redmine/db/migrate/20151021190616_change_user_preferences_hide_mail_default_to_true.rb

class ChangeUserPreferencesHideMailDefaultToTrue < ActiveRecord::Migration[4.2]
  def self.up
    change_column :user_preferences, :hide_mail, :boolean, :default => true
  end

  def self.down
    change_column :user_preferences, :hide_mail, :boolean, :default => false
  end
end