add phpbrew as a solution to handle PHP on Mac OSX

Readme.md

@@ -30,8 +30,8 @@ Requirements
 
 If you use Mac OSX, it still doesn't use php 5.4 as default php version... There are many solutions for you :
 
-* use linux (the best one)
-* use last MAMP version and put the php bin directory in your path  :
+* use [phpbrew](https://github.com/c9s/phpbrew)
+* use last MAMP version and put the php bin directory in your path:
 
 ```bash
 export PATH=/Applications/MAMP/bin/php/php5.4.x/bin/:$PATH