Improve .env.example (#3004)

* improve .env.example

* Update .env.example

Co-authored-by: Martin Stone <1611702+d7415@users.noreply.github.com>

---------

Co-authored-by: Martin Stone <1611702+d7415@users.noreply.github.com>

.env.example

@@ -102,9 +102,23 @@ DB_LIST_FOREIGN_KEYS=false
 # Support for token based authentication used by API requests. Enabled by default.
 # ENABLE_TOKEN_AUTH=true
 
+# Lychee supports both Redis and file caching.
+# To use Redis, set CACHE_DRIVER to redis and configure the Redis connection.
 CACHE_DRIVER=file
+REDIS_HOST=127.0.0.1
+REDIS_PASSWORD=null
+REDIS_PORT=6379
+# REDIS_URL=redis://<username>:<password>@<host>:<port>
+
+# If you use Redis as cache driver, we strongly recommend
+# to disable it for your Log Viewer.
+# Should redis crash, you will no longer be able to access your logs.
+LOG_VIEWER_CACHE_DRIVER=file
+
+# Session configuration
 SESSION_DRIVER=file
 SESSION_LIFETIME=120
+
 # `sync` if jobs needs to be executed live (default) or `database` if they can be defered.
 QUEUE_CONNECTION=sync
 
@@ -119,10 +133,6 @@ SECURITY_HEADER_CSP_IMG_SRC=
 SECURITY_HEADER_CSP_MEDIA_SRC=
 SESSION_SECURE_COOKIE=false
 
-REDIS_HOST=127.0.0.1
-REDIS_PASSWORD=null
-REDIS_PORT=6379
-
 MAIL_DRIVER=smtp
 MAIL_HOST=
 MAIL_PORT=