readme: info on how to select a different db

README.md

@@ -27,6 +27,9 @@ Simple example, included as `examples/simple.js`:
     var redis = require("redis"),
         client = redis.createClient();
 
+    // if you'd like to select database 3, instead of 0 (default), call
+    // client.select(3, function() { /* ... */ });
+
     client.on("error", function (err) {
         console.log("Error " + err);
     });