Memo:
for nginx people
if you have php-fpm installed you have to tell it that its user and group is nginx. /etc/php-fpm.d/www.conf . find user which is assigned to apache by default and change it to nginx. also do it for group. then run this command :
sudo service php-fpm restart
also inside of your wordpress directory execute these commands
sudo chown nginx:nginx * -R
sudo usermod -a -G nginx username
change username into what your current username is.
yet you have to apply propper permissions. run these commands inside your wordpress directory
sudo find . -type f -exec chmod 664 {} +
sudo find . -type d -exec chmod 775 {} +