Compression of data in Redis

[vovayartsev]

By default, the adapter encodes all the data via :erlang.term_to_binary/1 function which optionally accepts [:compressed] as a 2-nd argument. This option can reduce Redis memory consumption.

The compression rate depends on the nature of the data cached, so I decided to make it configurable on per-key basis (rather than on per-nebulex-cache-instance basis) by introducing :compressed data type:

@cache.set("foo", %{bar: 42}, dt: :compressed)