adds an inventory item

Example request

{
  "id": "d290f1ee-6c54-4b01-90e6-d701748f0851",
  "name": "Widget Adapter",
  "releaseDate": "2016-08-29T09:12:33.001Z",
  "manufacturer": {
    "name": "ACME Corporation",
    "homePage": "https://www.acme-corp.com",
    "phone": "408-867-5309"
  }
}