Search by area

https://trello.com/c/J74qWDAb/46-search-marketplace
boooo composite conditional spanning multiple lines.

Overall I think we have too much logic in here and we might want a Search model (not activerecord, just a ruby class with methods) to handle this. At a minimum, I'd like to see this as:

``` ruby
def search_price
  if price_range_specified?
    [...]
  end
end
```