Real-time communication with frontend

- Frontend shows heatmap of most visit places
- Maximum accuracy can now be set
- Fix bug where battery chart filtered values wrongly

backend/endpoints/beat.ts

@@ -35,7 +35,7 @@ export async function GetBeat(req: LivebeatRequest, res: Response) {
                     $gte: new Date((from | 0) * 1000),
                     $lte: new Date((to | Date.now() /1000) * 1000)
                 }
-            }).sort({ _id: -1 });
+            }).sort({ _id: 1 });
         res.status(200).send(beats);
     } else {
         res.status(404).send({ message: 'Phone not found' });