update collection/opendb-news-categories/collection.json.

collection/opendb-news-categories/collection.json

@@ -2,6 +2,12 @@
   "schema": {
     "bsonType": "object",
     "required": ["name"],
+    "permission": {
+      ".read": true, 
+      ".create": false,
+      ".update": false,
+      ".delete": false 
+    },
     "properties": {
       "_id": {
         "description": "存储文档 ID（文章 ID），系统自动生成"
@@ -33,7 +39,10 @@
       },
       "create_date": {
         "bsonType": "timestamp",
-        "description": "创建时间"
+        "description": "创建时间",
+        "defaultValue": {
+          "$env": "now"
+        }
       }
     }
   },