Setup a `domain` helper on the `postItem`.
Setup a `domain` helper on the `postItem`.

chapter3-2

alexkchan/hana,Wen777/Microscope,genjurosama/MeteorAtelier1,genjurosama/MeteorAtelier1,alexkchan/hana,dkim0526/newtncwebsite,dkim0526/newtncwebsite,domtkho/meteor-chapter-9-onwards,evodevnet/MeteorAtelier1,dkim0526/newtncwebsite,alexkchan/hana