Extract repeated phrase into method.
Instantiate less stuff in searches_controller.

Add two readers to Searcher to reduce the amount of instance variables
in the show method. Corresponding changes made in the view.

Adjust the search form partial, since it's tied to an instance of
Searcher.

Refactor Searcher to use the new shorter names. Use the readers where
instance variables were used before.
Don't allow blank category on an Item.
Change name of variable.
Move header partial to /app/views/application/.
Remove duplicate test.

This is already tested in user_adds_item_manually_spec.
Tweak long line split into something readable.
Remove superfluous line.
Remove some unnecessary stubbing.