def build(options = {})
      @stack.reverse.inject(nil) do |backend, (klass, opts)|
        klass.new backend, @options.merge(opts).merge(options)
      end
    end
def build(options = {})
      @stack.reverse.inject(nil) do |backend, (klass, opts)|
        klass.new backend, @options.merge(opts).merge(options)
      end
    end
Public: Generates wrapper instances for stack configuration.

 options - Hash of options that will be passed to all layers upon initialization.

 Returns top most Wrapper instance.