Updated doc

README.adoc

@@ -111,6 +111,7 @@ bucket4j.filters[0].cache-name=buckets # the name of the cache key
 bucket4j.filters[0].filter-method=servlet # [servlet,zuul,webflux,gateway]
 bucket4j.filters[0].filter-order= # Per default the lowest integer plus 10. Set it to a number higher then zero to execute it after e.g. Spring Security.  
 bucket4j.filters[0].http-response-body={ "message": "Too many requests" } # the json response which should be added to the body
+bucket4j.filters[0].http-response-headers.<MY_CUSTOM_HEADER>=MY_CUSTOM_HEADER_VALUE # You can add any numbers of custom headers
 bucket4j.filters[0].url=.* # a regular expression
 bucket4j.filters[0].metrics.enabled=true
 bucket4j.filters[0].metrics.types=CONSUMED_COUNTER,REJECTED_COUNTER # (optional) if your not interested in the consumed counter you can specify only the rejected counter