--- a/README.md	Sat Sep 06 00:08:18 2014 +0900
+++ b/README.md	Sat Sep 06 00:46:25 2014 +0900
@@ -26,12 +26,17 @@
 - `RT_CONSUMER_KEY`
 - `RT_CONSUMER_SECRET`
 
+Make sure to set them before using.
+
 Optionally, setting those two variables allows you access to private accounts which your account has access to:
 
 - `RT_ACCESS_TOKEN`
 - `RT_ACCESS_TOKEN_SECRET`
 
-Make sure to set them before using.
+It is also recommended to have memcached installed so tweet requests will be cached
+for a short while.
+
+- `RT_MEMCACHED_SERVERS` (separate multiple servers with comma)
 
 License
 -------