added docu for maps

README.md

@@ -111,7 +111,18 @@ satisfy: 'all
 ```
 
 **mapsconfig**:
+
+See https://nginx.org/en/docs/http/ngx_http_map_module.html#map
+
 ```
+# source variable name
+source: ''
+
+# destination variable name
+destination: ''
+
+# 'key: value' dict of values to map
+data: {}
 ```
 
 **phpconfog**: