creating rate limiting rule with mod_security

gistfile1.txt

http://sourceforge.net/p/mod-security/mailman/message/30634837/
    global and ip cannot be set per appid.

http://johnleach.co.uk/words/1073/rate-limiting-with-apache-and-mod-security
    basic rules for rate-limiting incoming traffic

https://www.digitalocean.com/community/tutorials/how-to-set-up-mod_security-with-apache-on-debian-ubuntu
    the instruction here helps in debugging mod_security
    
http://stackoverflow.com/questions/131681/how-can-i-implement-rate-limiting-with-apache-requests-per-second
    alternatives for rate limiting method. none suits my current need.
    
references:
* https://github.com/SpiderLabs/ModSecurity/wiki/Reference-Manual
* https://github.com/SpiderLabs/ModSecurity/wiki/ModSecurity-Frequently-Asked-Questions-(FAQ)