Move the `search_attributes` helper methods inside the Searchable
concern into a SearchContext helper class. This is so we don't have to
pass `params` and `current_user` down through a bunch of different
helper methods, and so that these private helper methods don't pollute
the object's namespace.
This directory contains library code used through Danbooru. This includes things like defining API clients, dealing with
sources, parsing tag searches, storing and resizing images, and so on.
Many of the files here use the Service Object pattern. Instead of putting complex code in models or controllers, it goes
here, in plain old Ruby objects (POROs). This keeps models and controllers simpler, and keeps domain logic isolated and
independent from the database and the HTTP request cycle.