geonames datasource with the timezone query for strongloop loopback

datasources.json

"geonames": {
  "name": "geonames",
  "debug": true,
  "connector": "rest",
  "operations": [
    {
      "template": {
        "doc": "GeoNames API: timezoneJSON",
        "method": "GET",
        "url": "http://api.geonames.org/timezoneJSON",
        "headers": {
          "content-type": "application/json",
          "accept": "application/json"
        },
        "query": {
          "lat": "{!lat}",
          "lng": "{!lng}",
          "username": "{!username}"
        },
        "variables": {
          "lat": {
            "type": "number",
            "format": "double",
            "required": true,
            "doc": "Lattitude"
          },
          "lng": {
            "type": "number",
            "format": "double",
            "required": true,
            "doc": "Longitude"
          }
        }
      },
      "functions": {
        "timezone": [
          "lat",
          "lng"
        ]
      }
    }
  ]
}