function getAllCity(req, res) {
  var promise = Q.fcall(function() {
    return City.find({}, function(err, cities) {
      if(err) {
        console.log(err);
        return res.send(404)
      }
      for (let i = 0; i < cities.length; i++) {
        Location.findOne({_id : cities[i].locationId}, function(err, location){
          if(err) return;
          cities[i].locationLng = location.lng;
          cities[i].locationLat = location.lat;
        });
      }
    });
  });
  promise.then(function(data) {
    console.log(data);
  }, function(err) {
    console.log(err);
  });
  // return res.json({isSucess: true, data: cities})
};