class ActiveResource::Errors

def from_hash(messages, save_cache = false)
  clear unless save_cache
  messages.each do |key,errors|
    errors.each do |error|
      add(key, error)
    end
  end
end

def from_json(json, save_cache = false)
  hash = ActiveSupport::JSON.decode(json)['errors'] || {} rescue {}
  from_hash hash, save_cache
end