Add a blurb about redis:32bit

redis/content.md

@@ -43,3 +43,7 @@ Alternatively, you can specify something along the same lines with `docker run`
 	docker run -v /myredis/conf/redis.conf:/usr/local/etc/redis/redis.conf --name myredis redis redis-server /usr/local/etc/redis/redis.conf
 
 Where `/myredis/conf/` is a local directory containing your `redis.conf` file. Using this method means that there is no need for you to have a Dockerfile for your redis container.
+
+## `32bit` variant
+
+This variant is *not* a 32bit image (and will not run on 32bit hardware), but includes Redis compiled as a 32bit binary, especially for users who need the decreased memory requirements associated with that. See ["Using 32 bit instances"](http://redis.io/topics/memory-optimization#using-32-bit-instances) in the Redis documentation for more information.