Undocumented behaviour for mass releasing features

[pcasaretto]

Currently, release accepts an array and because Redis.scard accepts it as well it ends ups releasing that feature to all ids present in the array.
This is undocumented behaviour and future storage options might not implement this.

> FeatureFlagger.control.release("feature1", [1,2,3])
> FeatureFlagger.control.rollout?("feature1", 1) #=> true
> FeatureFlagger.control.rollout?("feature1", 2) #=> true
> FeatureFlagger.control.rollout?("feature1", 3) #=> true

[nsoufr]

Wowwwwwwwwww

[nsoufr]

After almost three years of thinking...

We should definitely make the #release method accepts arrays natively, so other storages could rely on this behavior and expect both string|integers or string|integer arrays.