Shrine

Possible memory leak when searching for storage

To find a storage the supplied name is being converted using #to_sym to search key symbols inside the @storages hash.

If an input field for upload file JSON is subject to abuse having a user submit the following attempts: '{"id":"file.jpg", "storage":"store1"}'
'{"id":"file.jpg", "storage":"store2"}'
'{"id":"file.jpg", "storage":"store3"}'
When shrine tries to find the storages, 3 new symbols are added to the app [:store1, :store2, :store3].

I don’t know if an issue should be created, because in more recent versions of ruby, under some circumstances symbols are now garbage collected.
But I felt more comfortable if the logic was converting symbols to strings and compare the strings, instead of converting strings to symbols for comparison.