fix docs

docs/endpoint.md

@@ -45,15 +45,19 @@ body: (content-type: application/json)
 ```html
 
     http|https
-    {"url": "http(s)://xx.com"}
+        {"url": "http(s)://xx.com"}
 
     websocket
-    {"url": "ws://xx.com/ws"}
+        {"url": "ws://xx.com/ws"}
 
     kafka:
-    {"bootstrap_server": ["localhost:9092"], "topic": "test", "username": "test", "password": "password1234"}
+        {"bootstrap_server": ["localhost:9092"], "topic": "test", "username": "test", "password": "password1234"}
+    
+    mysql:
+        {"host": "localhost", port: 3306, "username": "test", "password": "test1234", "database": "iot", "table_name": "north_data"}
+    
     mqtt:
-    {"host": "localhost", port: 1883, "username": "test", "password": "test1234", "topic": "CET/NX/${location_code}/upload", "qos": 0|1|2}
+        {"host": "localhost", port: 1883, "username": "test", "password": "test1234", "topic": "CET/NX/${location_code}/upload", "qos": 0|1|2}
 
     topic中支持预定义变量: ${location_code}; 发送的时候会替换成对应的点位编码
 ```