docs: add cache base option example & description

docs/content/1.guide/1.introduction/5.cache.md

@@ -17,6 +17,7 @@ const cachedFn = cachedEventHandler(fn, options)
 - `integrity`: A value that changing it, will invalidate all caches for function. By default will be computed from **function code**.
 - `maxAge`: Maximum age that cache is valid in seconds. Default is `1` second.
 - `swr`: Enable Stale-While-Revalidate behavior. Enabled by default.
+- `base`: Name of the storage mointpoint to use for caching (`/cache` by default)
 
 
 ## Examples
@@ -54,3 +55,28 @@ export default defineNitroConfig({
   }
 })
 ```
+
+
+**Example:** Set cache storage mountpoint for a group of routes (**🧪 Experimental!**)
+
+```js
+// nitro.config.ts
+import { defineNitroConfig } from 'nitropack'
+
+export default defineNitroConfig({
+  storage: {
+    'my-custom-storage': {
+      driver: 'redis',
+      url: 'redis://localhost:6379'
+    }
+  },
+  routeRules: {
+    '/blog/**': { 
+      swr: true,
+      cache: {
+        base: '/my-custom-storage'
+      }
+    }
+  }
+})
+```