feat: add deduplication doc

content/smartmodules/deduplication.md

@@ -0,0 +1,41 @@
+---
+title: Deduplication
+---
+
+The `Deduplication` feature in Fluvio is the way to deduplicate records based on their keys.
+
+Deduplication can be used on a topic directly, or it can be used on connectors. It will drop the duplicate records on a configured window.
+
+This window is defined by the parameters passed to the filter smartmodule.
+
+## Example topic config
+
+Example configuration on topic:
+
+%copy%
+```yaml
+# topic.yaml
+version: 0.1.0
+meta:
+  name: topic-with-dedup
+deduplication:
+  bounds:
+    count: 5 # remember at least 5 last records
+    age: 5s # remember records for at least 5 seconds
+  filter:
+    transform:
+      uses: infinyon-labs/dedup-filter@0.0.1  
+```
+A topic can be created using this config file like so:
+
+%copy first-line%
+```bash
+$ fluvio topic create -c topic.yaml
+```
+
+## Parameters
+
+| Parameter       | default | type   | optional | description                                           |
+|:-------------|:--------| :---   | :---   |:------------------------------------------------------|
+| count |    -    | Integer | false | Minimum number of records the filter will remember. It doesn't guarantee to remember records that came `count` records before now. |
+| age   |    -    | Integer | true | Minimum amount of time this filter will remember a record for. It can be specified using this format: `15days 2min 2s`, or `2min 5s`, or `15ms` | |