Right here we go,
2 diodes, 1 protects the xAC the other helps suppress emf when the relay turns off.
I included the capacitor, this is optional. It will keep the relay on for a brief amount of time after the tag has scanned. (Needs to be big think 50uF+ 15v rated minimum)
As stated earlier only one relay is needed unless you need to drive a very large load.
EDIT: Looks like everyone wanted a go 