class User < ActiveRecord::Base
  has_settings do |s|
    s.key :dashboard, :defaults => { :theme => 'blue', :view => 'monthly', :filter => false }
    s.key :calendar,  :defaults => { :scope => 'company'}
  end
end

class User < ActiveRecord::Base
  has_settings :dashboard, :calendar
end

class Project < ActiveRecord::Base
  has_settings :info, :class_name => 'ProjectSettingObject'
end

class ProjectSettingObject < RailsSettings::SettingObject
  validate do
    unless self.owner_name.present? && self.owner_name.is_a?(String)
      errors.add(:base, "Owner name is missing")
    end
  end
end

user = User.find(1)
user.settings(:dashboard).theme = 'black'
user.settings(:calendar).scope = 'all'
user.settings(:calendar).display = 'daily'
user.save! # saves new or changed settings, too

user = User.find(1)
user.settings(:dashboard).update_attributes! :theme => 'black'
user.settings(:calendar).update_attributes! :scope => 'all', :display => 'dialy'

user = User.find(1)
user.settings(:dashboard).theme
# => 'black

user.settings(:dashboard).view
# => 'monthly'  (it's the default)

user.settings(:calendar).scope
# => 'all'

User.with_settings
# => all users having any setting

User.without_settings
# => all users without having any setting

User.with_settings_for(:calendar)
# => all users having a setting for 'calender'

User.without_settings_for(:calendar)
# => all users without having settings for 'calendar'

gem 'ledermann-rails-settings', :require => 'rails-settings'