Implement loader for Rails 3 1 session string by a Rails 3 0 app
user
```ruby
module FlashPatch
  class Rails31SessionLoader
    def initialize(decrypted_session_string)
      @decrypted_session_string = decrypted_session_string
    end

    def load_session
      session = Marshal.load @decrypted_session_string.gsub('FlashHash','FlashGash')
      flash_messages_from_original_klass = session.delete('flash')
      session['flash'] = ActionDispatch::Flash::FlashHash.new.update(flash_messages_from_original_klass)
      session
    end
  end
end
```
assistant