There’s one little problem with the solution to exercise 3. While the solution shows you how to use memcached, it is not a solution that will be fault tolerant under high load. Modify the solution to...

There’s one little problem with the solution to exercise 3. While the solution shows you how to use memcached, it is not a solution that will be fault tolerant under high load. Modify the solution to exercise 3 so that it uses the Redis key-value database instead. The Redis key-value database is just like memcached, except that it also stores data persistently on disk. Download Redis from http://redis.io and use the redis-node module from https://github .com/bnoguchi/redis-node.