No css/js or images found on heroku deployment octobercms

I have deployed my octobercms site on heroku successfully but it is not loading any css/js or image file. All links go to 404. External links are loaded but no local link is working. I have deployed it using Github.

I have tried all of solutions I found anywhere on web but none of them works. All laravel solutions are not working. I can't even access any file manually. Functionality of site is working normally.

currently this is how links are included:

  <link type="text/css" href="assets/css/custom.css" rel="stylesheet">

and this is how they are shown when rendered:

<link type="text/css" href="http://pandak-farms.herokuapp.com/themes/codejunkie/assets/css/custom.css" rel="stylesheet">

links should open but all of them are pointing to 404. demo: http://pandak-farms.herokuapp.com/themes/codejunkie/assets/css/argon.css?v=1.0.1

via Chebli Mohamed