eventClick: function (calEvent, jsEvent, view) {
    $.ajax({
       url: 'calendar/remove_event.php',
       data: 'id=' + event.id,
       type: "POST",
       success: function () {
          $('#calendar').fullCalendar('removeEvents', calEvent._id);
       }
   });
},

$id = $_POST['id'];

$ligacao = mysqli_connect("localhost", "root", "", "mydatabase");
if (mysqli_connect_errno()) {
    echo "Can't connect to database: " . mysqli_connect_error();
}

$sql = "delete from events WHERE id= '$id'";
$resultado = mysqli_query($ligacao, $sql);
mysqli_close($ligacao);