I'm thinking of killing the `store_options` - it looks too much. An more friendly approach would be to expect everything in the `store` key. 

```ruby
builder.use :http_cache, store: Rails.cache
builder.use :http_cache, store: [:mem_cache_store, ['localhost:11211']]
builder.use :http_cache, store: [:file_store, '/tmp']
```

The `Storage` initialize` can just pass everything under the `store` key and AS will take care of it. Wdyt?