Caching not working with RedisStore Cache

Using Rails.cache as a resource_cache appears to make the caching fail when config.cache_store is redis_store.

I think the reason is due to the way Redis Cache serialise key as string when they are arrays.

When the key(an array) is serialised in the self.write method of CachedResourceFragment
https://github.com/cerebris/jsonapi-resources/blob/master/lib/jsonapi/cached_resource_fragment.rb#L122 it is serialised as a string.
When the value is retrieved in the lookup method the hash hits returned by the read_multi methods has keys that are not array, but strings. The method has_key? is then failing returning false instead of true.
https://github.com/cerebris/jsonapi-resources/blob/master/lib/jsonapi/cached_resource_fragment.rb#L81

Simple example, with config.cache_store = :redis_store

Rails.cache.write([1,2], 'value')
hash = Rails.cache.read_multi([1,2])
# returns false
hash.has_key?([1,2])

I've tried to serialise manually the keys (https://github.com/cerebris/jsonapi-resources/compare/master...x4d3:master) without success, the test are failing.

Thank you,

Beginne in lib/jsonapi/cached_resource_fragment.rb bei lookup und self.write und reproduziere anschließend das Beispiel für Rails.cache.read_multi mit config.cache_store auf :redis_store gesetzt. Vergleiche die von RedisStore zurückgegebenen Schlüsseltypen mit den von has_key? verwendeten Array-Schlüsseln; abgeschlossen ist die Aufgabe, wenn Cache-Treffer erkannt werden und die bestehenden Tests bestehen.