public function start(Request $request)
 {
     $task_id = $request->input('task_id');
     $stopped = $this->stopActive();
     $tracking = new Tracking();
     $tracking->user_id = Auth::user()->id;
     $tracking->task_id = $task_id;
     $tracking->started_at = date('Y-m-d H:i:s');
     $tracking->active = 1;
     $tracking->save();
     return ['stopped' => $stopped, 'started' => ['task_id' => $task_id, 'active' => true]];
 }