json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "additionalProperties": false,
      "properties": {
          "email": {
              "_format": "email",
              "maxLength": 1024,
              "type": "string"
          },
          "role": {
              "enum": [
                  "admin",
                  "edit",
                  "view"
              ],
              "type": "string"
          }
      },
      "required": [
          "email",
          "role"
      ],
      "type": "object"
  }