public function postComment(Request $request)
{
$this->validate($request, ['fileId' => 'required|integer', 'start' => 'required|integer', 'end' => 'required|integer', 'content' => 'required|max:256|string']);
$comment = new Comment();
$comment->file_id = $request->input('fileId');
$comment->start = $request->input('start');
$comment->end = $request->input('end');
$comment->content = $request->input('content');
$comment->save();
return $comment->toJson();
}
