Fix Strict-Transport-Security response header not set (#5)

Author: wborn

haproxy.cfg

@@ -107,7 +107,7 @@ frontend https
     http-request add-header X-Forwarded-Proto https
     http-request set-header X-Forwarded-Host %[req.hdr(Host)]
     http-request add-header X-Forwarded-Port %[dst_port]
-    http-request add-header Strict-Transport-Security max-age=15768000
+    http-response add-header Strict-Transport-Security max-age=15768000
 
     # Gateway tunnelling config
     .if defined(SISH_HOST) && defined(SISH_PORT)