Adding to JSON in PostgreSQL

dbtest.js

var playerSchema = {
  "steam_id": null,
  "steam_username": null,
  "steam_avatar_url": null,
  "total_items_deposited_value": null,
  "total_num_items_deposited": null,
  "items": [{
    "appid": null,
    "contextid": null,
    "classid": null,
    "instanceid": null,
    "icon_url": null,
    "name": null,
    "market_hash_name": null,
    "median_price": null
  }]
};

function UpdateRoundPlayers() {
  var players = [];
  pg.connect(connectionString, function(err, client, done) {
    var query = client.query("SELECT players FROM rounds ORDER BY game_id DESC LIMIT 1");
    query.on('row', function(row) {
     players.push(row.players);
    });
    query.on('end', function() {
      var updated = [];
      if(players[0] == null) {
        updated = [playerSchema];
      }
      else {
        updated = players.concat(playerSchema);
      }
      console.log(updated);
      var x = [];
      pg.connect(connectionString, function(err, client, done) {
        client.query("UPDATE rounds SET players=($1) WHERE game_id=(SELECT MAX(game_id) FROM rounds)", [JSON.stringify(updated)]);
        var query = client.query("SELECT players FROM rounds ORDER BY game_id DESC LIMIT 1");
        query.on('row', function(row) {
          x.push(row);
        });
        query.on('end', function() {
          client.end();
          console.log(x);
        });
        if (err) {
          console.log(err);
        }
      });
    });
    if (err) {
      console.log(err);
    }
  });
}