fix readme

Author: jiehanzheng

README.md

@@ -44,13 +44,12 @@ It is certainly a good idea to make a cron job for this.
 
 You should also read [SquidFaq/SquidLogs](http://wiki.squid-cache.org/SquidFaq/SquidLogs#access.log) to make sure your log files are in reasonable sizes.
 
---exclude-pattern
------------------
+### --exclude-pattern
 
 If for some reason you need to prevent usage information of certain user from being sent to the RADIUS server, there is an argument for that!  Use `--exclude-pattern="(girl|boy)friend"` and squid2radius won't send usage of either your `girlfriend` or `boyfriend` to the RADIUS server.
 
 Note
-====
+----
 
 The script assumes that you are using the default [Squid native access.log format](http://wiki.squid-cache.org/Features/LogFormat#squid) on first ten columns of your log file.  If you need custom columns, add them after the default ones.