The database interaction actor

We start by implementing an actor that interacts with a database. Copy the previous example and add the redis crate to the dependencies:

redis = "0.9"

We use Redis because it's great for caching, but we can also store cached values in memory.

Create a src/cache.rs module and add the following dependencies:

use actix::prelude::*;
use failure::Error;
use futures::Future;
use redis::{Commands, Client, RedisError};

It adds types from the redis crate that we already used in Chapter 7, Reliable Integration with Databases, to interact with Redis storage.