Avoid hset on the storage if the value did not change

Author: andrehjr

lib/split/persistence/redis_adapter.rb

@@ -27,7 +27,7 @@ def [](field)
       end
 
       def []=(field, value)
-        Split.redis.hset(redis_key, field, value.to_s)
+        Split.redis.hset(redis_key, field, value.to_s) if self[field] != value.to_s
         expire_seconds = self.class.config[:expire_seconds]
         Split.redis.expire(redis_key, expire_seconds) if expire_seconds
       end