createLineChart: function (id, history, min, max) {
            var ctx = document.querySelector('#' + id).getContext("2d");
            for (var i = 0; i < history.length; i++) {
                history[i] = Math.round(history[i] * 100) / 100;
            }
            var lineChartData = {
                labels: ['', '', '', '', ''],
                datasets: [
                    {
                        label: id,
                        fillColor: "rgba(56,142,60,0.4)",
                        strokeColor: "rgba(56,142,60,1)",
                        pointColor: "rgba(56,142,60,1)",
                        pointStrokeColor: "#fff",
                        pointHighlightFill: "#fff",
                        pointHighlightStroke: "rgba(56,142,60,1)",
                        data: history
                    },
                    {
                        //an empty dataset to trigger custom tooltips
                    }
                ]
            };
            var c = new Chart(ctx).Line(lineChartData, {
                responsive: true
            });
        }