Add missing attr.rs file
Add missing attr.rs file

tempbottle/serde,thorbenk/serde,infinityb/serde,erickt/serde,jmesmon/serde,JohnHeitmann/serde,oli-obk/rust-serde,csmulhern/serde,Byron/serde,sidred10/serde,3Hren/serde,Hoverbear/serde,Ticki/serde,pcwalton/serde,skade/serde,eefriedman/serde,serde-rs/serde