Add a fileType field into the index

api/internal/crawl/search_cmds/misc.md

@@ -16,4 +16,17 @@ curl -X GET "${ElasticSearchURL}:9200/${INDEXNAME}/_mapping?pretty"
 Delete the kustomize index from the ElasticSearch cluster (**Use this command with caution**):
 ```
 curl -X DELETE "${ElasticSearchURL}:9200/${INDEXNAME}?pretty"
+```
+
+Add a new field into an existing index.
+```
+curl -X PUT "${ElasticSearchURL}:9200/${INDEXNAME}/_mapping/_doc?pretty" -H 'Content-Type: application/json' -d'
+{
+  "properties": {
+    "fileType": {
+      "type": "keyword"
+    }
+  }
+}
+'
 ```