Add a configuration example for Redis (#36)

* Add a configuration example for Redis

With the StashPHP documentation, it was not clear how to use Redis.

This adds an example on how to use Redis in combination with DDEV.

* Update README.md

Co-authored-by: Orestis Samaras <66624212+o-samaras@users.noreply.github.com>
Signed-off-by: Bernhard Kau <github@kau-boys.de>

---------

Signed-off-by: Bernhard Kau <github@kau-boys.de>
Co-authored-by: Orestis Samaras <66624212+o-samaras@users.noreply.github.com>

Author: 2ndkauboy

README.md

@@ -90,12 +90,18 @@ WP_STASH_DRIVER=\Stash\Driver\FileSystem
 WP_STASH_DRIVER_ARGS='{"path":"\/var\/www\/cache","dirSplit":1}'
 ```
 
-Caching to a memcached server at `localhost`:
+Caching with a memcached server using the `memcached` host name (e.g. in DDEV):
 ```
 WP_STASH_DRIVER=\Stash\Driver\Memcache
 WP_STASH_DRIVER_ARGS='{"servers":["memcached","11211"]}'
 ```
 
+Caching with a Redis server using the `redis` host name (e.g. in DDEV):
+```
+WP_STASH_DRIVER=\Stash\Driver\Redis
+WP_STASH_DRIVER_ARGS='{"servers":[{"server":"redis", "port":6379}]}'
+```
+
 Don't cache persistently at all (cache lives only within the script lifetime):
 ```
 WP_STASH_DRIVER=\Stash\Driver\Ephermal