In case you are on Ubuntu, edit the file /etc/apache2/apache2.conf (here we have an example of /var/www):

<Directory /var/www/>
Options Indexes FollowSymLinks
AllowOverride None
Require all granted
</Directory>

and change it to;

<Directory /var/www/>
Options Indexes FollowSymLinks
AllowOverride All
Require all granted
</Directory>

then,

sudo service apache2 restart

You may need to also do sudo a2enmod rewrite to enable module rewrite.