document the cluster backend

Author: amirreza8002

docs/.nav.yml

@@ -6,8 +6,9 @@ nav:
 
   - configure
   - async
+  - cluster
   - commands
 
   - migration_from_django_redis.md
   - customize.md
-  - changes.md
+  - changes.md

docs/cluster/.nav.yml

@@ -0,0 +1,2 @@
+nav:
+  - basic_configurations.md

docs/cluster/basic_configurations.md

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+# Basic cluster configuration
+
+for installation, look at our [Installation guide](../installation.md)
+
+
+## Configure as cache backend
+
+to start using django-valkey's cluster backend, change your django cache setting to something like this:
+
+```python
+CACHES = {
+    "default": {
+        "BACKEND": "django_valkey.cluster_cache.cache.ClusterValkeyCache",
+        "LOCATION": "valkey://127.0.0.1:6379",
+        "OPTIONS": {...}
+        }
+    }
+```
+
+you need to point to at least one of the cluster nodes in `LOCATION`, or pass a list of multiple nodes
+
+at the moment, only one client is avilable for cluster backend
+
+most of the configurations you see in [basic configuration](../configure/basic_configurations.md) and [advanced configuration](../configure/advanced_configurations.md)
+apply here as well, except the following:
+
+
+
+### Memcached exception behavior
+in [Memcahed exception behavior](../configure/basic_configurations.md#memcached-exception-behavior) we discussed how to ignore and log exceptitions,
+sadly, until we find a way around it, this is not accessable with cluster backend
+
+
+## Multi-key Commands
+
+please refer to [valkey-py docs](https://valkey-py.readthedocs.io/en/latest/clustering.html#multi-key-commands) on how to use multi-key commands, such as `mset`, `megt`, etc...
+
+there are some other info in their documentations that might be of interest to you, we suggest you take a look
+
+
+## Additional methods
+in addition to what other `django-valkey` clients provide, cluster client supports the following methods:
+
+* mset_nonatomic (same as `set_many`)
+* msetnx
+* mget_nonatomic (same as `get_many`)
+* readonly
+* readwrite
+* keyslot
+* flushall
+* invalidate_key_from_cache