code: def delete_cache(key_name)
        [cache_key_for(key_name), "views/#{cache_key_for(key_name)}"].each do |key|
          Rails.cache.delete(key)
        end
      end
docs: the rails helper method 'cache (name, opts) do ...'
   adds some extras to the cache key.
   To run with this gem, you have to add 'skip_digest: true'.
   Any other options will prevent correct cache deletion!!