Add high-level test for searching.

Test fails due to unimplemented Searcher class.
Implemented basic version of Searcher class.

Currently only the titles of returned items can be returned.
Searches are made without any category specification.
Make item searching spec use VCR.
Add figaro gem to handle env and add README.
Reorder Gemfile.
Add rendering of search items.
Fix scenario description.
Add categories to searching.

Pass around Category objects instead of category name strings.
Extract Item::CATEGORIES into Category::NAMES.
Generate new VCR cassette due to inclusion of category in Amazon search.
Don't include implementation in method name.
Use the word 'copy' in README, not 'remove'.
Use String#pluralize.
Place constants together.
Extract variable to a query method.
Rename file to reflect Gem name.
Use Category.all instead of Item::CATEGORIES.
Add Category.find_by_name method.
Rewrite tests for Category.find_by_name.
Use Category#name reader for increased clarity.
Add adding of items from search results.
Style the titles.