Search by Property Category

* Update search logic in listing controller
* Add room category to fields to forms
* Update search results controller
* The room category commit should be swapped with this commit
https://trello.com/c/F9jyfw3A
Formatting is weird. Also, you'll want to skip empty strings (since they'll read as double spaces)! Try:

```ruby
[
  params[:city],
  ...,
  params[:room_categories]
].select(&:present?).join(" ")
```