router.post('/add', uploadProductImage, (req, res, next) => {
  const { name, description, providerId, price } = req.body
  const img = req.file

  waterfall([
    (cb) => {
      gm(img.path)
        .resize(320, 240)
        .noProfile()
        .write(__dirname + '/../public/images/products/' + img.filename, (err) => cb(err))
    },
    (cb) => {
      deleteFile(img.path, (err) => cb(err))
    },
    (cb) => {
      const product = new Product({
        name,
        description,
        img: img ? img.filename : 'no-photo',
        providers: [{
          price: price,
          id: providerId,
        }],
      })
      product.save((err, item) => cb(err, item))
    }
  ],(err, item) => {
    if (err) {
      return res.status(400).json({ error: err.message })
    }
    return res.json({ data: item })
  })
})