Draft error responses for Bootic's API

bootic_entity_with_errors.json

{
  "class": ["errors", "product"],
  "links": {
    "schema": {"href":"..."}
  },
  "properties": {
    "title": "iphone",
    "id": null,
    "slug":"apple-iphone"
  },
  "errors": [
    {
      "code": "missing",
      "property": "title",
      "message": "Cannot be empty"
    },
    {
      "code": "duplicated",
      "property": "slug",
      "message": "Already exists"
    }
  ],
  "entities": {

    "variants": [
      {
        "class": ["errors", "variant"],
        "properties": {
          "title": ""
        },
        "errors": [
          {"code": "missing", "property": "title", "message":"Cannot be empty"}
        ]
      }
    ]
  }
}