calefaction/app/models/admin_setting.rb

class AdminSetting < ActiveRecord::Base

  def self.get(key)
    Rails.cache.fetch("admin_setting/#{key}") do
      self.find_by(key: key).value
    end
  end

  def self.set(key, value)
    setting = self.find_by(key: key)
    setting.update(value: value)
    Rails.cache.write("admin_setting/#{key}") do
      value
    end
  end
end