$('#tracker').detach().prependTo($('#sidebar')).removeClass('hidden');
$('#tracker_button').on('click', function() { start_tracking($('#tracker_username').val()) });
$('#tracker_stop').on('click', stop_tracking);
$('#tracker').detach().prependTo($('#sidebar')).removeClass('hidden');
$('#tracker_button').on('click', function() { start_tracking($('#tracker_username').val()) });
$('#tracker_stop').on('click', stop_tracking);