Hi guys how can I backup all my contacts before I restore my iPhone?

iTunes backs it up for you.

The contacts shuld stay intact after you update nut just in case you have problems like i did and you need to restore you can back upd your contacts file

the contacts are stored in a file called : AddressBook.sqlitedb
you can copy it to your computer using ibrickr or WinSCP
the file is located in this Directory:

var / root / Library / AddressBook /