i have enabled extension=php_pdo_pgsql.dll and extension=php_pgsql.dll in my php.ini file but still unable to get adminer to work.
and also sudo service apache2 restart
sudo apt-get install php7.0-pgsql
cd /etc/postgresql/9.5/main
sudo nano pg_hba.conf
local all postgres peer
should be
local all postgres md5
sudo service postgresql restart
then you good to go :)