fetch('/api/days/task/add/', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    dayid: '59455bc0a96a7810a0595306',
    title: 'Запись',
    price: 1000,
  }),
})
.then(res => res.json())