Users can create a listing

https://trello.com/c/2Ma1JSBO/3-as-a-user-i-can-list-a-room-apartment-house

![image](https://cloud.githubusercontent.com/assets/8646429/4981664/2bdf780e-690b-11e4-870e-651855627d44.png)

By "whole thing" I mean "everything inside `@listings.each`"