app/controllers/extface/devices_controller.rb
def create
      @device = extfaceable.extface_devices.new(device_params)
      if @device.save
        redirect_to @device, notice: 'Device was successfully created.'
      else
        render action: :form
      end
    end
def create
      @device = extfaceable.extface_devices.new(device_params)
      if @device.save
        redirect_to @device, notice: 'Device was successfully created.'
      else
        render action: :form
      end
    end
POST /devices