Update security.md and include 37 bit calculation
Update security.md and include 37 bit calculation

closes #21
adhintz/password-alert,adhintz/password-alert,yubbie/password-alert,yubbie/password-alert,Shekharrajak/password-alert,PickmanSec/password-alert,google/password-alert,Shekharrajak/password-alert,yubbie/password-alert,google/password-alert,adhintz/password-alert,Shekharrajak/password-alert,yubbie/password-alert,google/password-alert,PickmanSec/password-alert,adhintz/password-alert,PickmanSec/password-alert,PickmanSec/password-alert,Shekharrajak/password-alert,google/password-alert