update README with notes about custom filters
update README with notes about custom filters

emrass/fail2ban,opscode-cookbooks/fail2ban,emrass/fail2ban,opscode-cookbooks/fail2ban,aleksandrs-ledovskis/fail2ban-cookbook,gorazio/chef-fail2ban,chef-cookbooks/fail2ban,bumi/fail2ban,aleksandrs-ledovskis/fail2ban-cookbook,chef-cookbooks/fail2ban,gorazio/chef-fail2ban