Update README.md

Author: Taymindis

README.md

@@ -8,22 +8,34 @@ For body filter before proxy to backend
 Example:
 
 ```nginx
-    error_page 418 =200 /welcome_if_request_body;
-    location /welcome_if_request_body {
-        add_header Content-Type text/plain;
-        return 200 "welcome_if_request_body, you hit it";
+http {
+  ....
+    
+    map "$uri" $forward_status {
+        default 100; # 100 means nothing return, continue to proxy phase
+        "~*.+?\.(css|js|bmp|gif|ico|jpeg|jpg|pict|png|svg|swf|tif)$" 418;
     }
 
-    location = / {
-        if_request_body on;
-        return_status_if_body_eq "ASD" 418 on;
-        return_status_if_body_eq "foo" 418;
-        return_status_if_body_eq "john" 418;
-        return_status_if_body_startswith "report" 418;
-        return_status_if_body_contains "report" 418;
-        return_status_if_body_regex "^[\d]+?abc" 418;
-        proxy_pass http://localhost:7777;
-        
-    }
+  server {
+   ...
+        error_page 418 =200 /welcome_if_request_body;
+        location /welcome_if_request_body {
+            add_header Content-Type text/plain;
+            return 200 "welcome_if_request_body, you hit it";
+        }
+
+        location = / {
+            if_request_body on;
+            return_status_if_body_eq "ASD" 418 on;
+            return_status_if_body_eq "foo" 418;
+            return_status_if_body_eq "john" 418;
+            return_status_if_body_startswith "report" 418;
+            return_status_if_body_contains "report" 418;
+            return_status_if_body_regex "^[\d]+?abc" 418;
+            proxy_pass http://localhost:7777;
 
+        }
+...
+    }
+}
 ```