Install Phalcon on Ubuntu 12.04

1. We need some packages previously installed:
> sudo apt-get install php5-dev php5-mysql gcc libpcre3-dev


2. create the extension from C source
> git clone --depth=1 git://github.com/phalcon/cphalcon.git
> cd cphalcon/build
> sudo ./install

3. Add the extension to your php.ini:
extension=phalcon.so

4. Finally, restart the webserver
> sudo service apache2 restart