refactor: use for page function for pagination

[alipowerful7]

before:

$this->offset(($page - 1) * $perPage)->limit($perPage + 1);

after:

$this->forPage($page, $perPage);

if method call with perPage 15 in this one

$this->offset(($page - 1) * $perPage)->limit($perPage + 1);

perPage is 16

[taylorotwell]

If this is working I'd rather not change it.