docs: add runtime storage configuration examples (#22189)

docs/2.guide/2.directory-structure/1.server.md

@@ -340,10 +340,12 @@ Never combine `next()` callback with a legacy middleware that is `async` or retu
 
 ### Server Storage
 
-Nitro provides a cross-platform [storage layer](https://nitro.unjs.io/guide/storage). In order to configure additional storage mount points, you can use `nitro.storage`.
+Nitro provides a cross-platform [storage layer](https://nitro.unjs.io/guide/storage). In order to configure additional storage mount points, you can use `nitro.storage`, or [server plugins](#server-plugins).
 
 #### Example: Using Redis
 
+Using `nitro.storage`:
+
 ```ts [nuxt.config.ts]
 export default defineNuxtConfig({
   nitro: {
@@ -363,6 +365,43 @@ export default defineNuxtConfig({
 })
 ```
 
+Alternatively, using server plugins:
+
+::code-group
+
+```ts [server/plugins/storage.ts]
+import redisDriver from 'unstorage/drivers/redis'
+
+export default defineNitroPlugin(() => {
+  const storage = useStorage()
+
+  // Dynamically pass in credentials from runtime configuration, or other sources
+  const driver = redisDriver({
+      base: 'redis',
+      host: useRuntimeConfig().redis.host,
+      port: useRuntimeConfig().redis.port,
+      /* other redis connector options */
+    })
+
+  // Mount driver
+  storage.mount('redis', driver)
+})
+```
+
+``` ts [nuxt.config.ts]
+export default defineNuxtConfig({
+  runtimeConfig: {
+    redis: { // Default values
+      host: '',
+      port: 0,
+      /* other redis connector options */
+    }
+  }
+})
+```
+
+::
+
 Create a new file in `server/api/test.post.ts`:
 
 ```ts [server/api/test.post.ts]