docs(README): add custom response usage

README.md

@@ -138,6 +138,10 @@ excludes: []
 whitelists: []
 customs: []
 customs_from_file: ""
+response:
+    status: 0
+    html: ""
+    html_file: ""
 log_file: ""
 no_stderr: false
 no_update_check: false
@@ -150,10 +154,15 @@ Or the equivalent in JSON format:
 
 ```json
 {
-  "excludes": null,
-  "whitelists": null,
-  "customs": null,
+  "excludes": [],
+  "whitelists": [],
+  "customs": [],
   "customs_from_file": "",
+  "response": {
+    "status": 0,
+    "html": "",
+    "html_file": ""
+  },
   "log_file": "",
   "no_stderr": false,
   "no_update_check": false,
@@ -185,6 +194,10 @@ Customs from file (**customs_from_file**) specifies the file path or glob patter
 
 The glob pattern supports wildcards, allowing you to specify multiple files or a directory with matching files. For example, "/path/to/custom/rules/\**/*.yaml" will load all YAML files in the "rules" directory and its subdirectories. Please refer to the [docs](https://github.com/kitabisa/teler-waf#custom-rules).
 
+### Custom Response
+
+Response (**response**) is the configuration for custom error response pages when a request is blocked or rejected. Please refer to the [docs](https://github.com/kitabisa/teler-waf#custom-response).
+
 ### Log File
 
 Log file (**log_file**) is the file path (`string`) for the log file to store the security logs. If `log_file` is specified, log messages will be written to the specified file in addition to stderr (if `no_stderr` is **false**).