begin y at 0

static/js/histogram.js

@@ -59,6 +59,13 @@ function setData(data) {
             title: {
                 display: true,
                 text: 'Histogram of times of lessons'
+            },
+            scales: {
+                yAxes: [{
+                    ticks: {
+                        beginAtZero: true
+                    }
+                }]
             }
         }
     }).update();