json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "type": "object",
      "required": [
          "id",
          "category",
          "priority",
          "content"
      ],
      "properties": {
          "created": {
              "type": "string",
              "format": "date-time"
          },
          "modified": {
              "type": "string",
              "format": "date-time"
          },
          "id": {
              "type": "string"
          },
          "category": {
              "type": "string"
          },
          "priority": {
              "type": "string"
          },
          "content": {
              "type": "object",
              "minProperties": 1,
              "additionalProperties": {
                  "type": "string"
              }
          }
      }
  }