PHRAS-3859 fix gateway fastcgi https default value (#4329)

.env

@@ -182,13 +182,17 @@ PHRASEANET_MAINTENANCE=0
 # on IP and/or password
 # @run
 # configuration exemple :
-#GATEWAY_ALLOWED_IPS=10.0.0.1,10.0.1.1
-#GATEWAY_DENIED_IPS=172.1.0.1,172.1.0.2
-#GATEWAY_USERS="user1:password1,user2:password2"
+# GATEWAY_ALLOWED_IPS=10.0.0.1,10.0.1.1
+# GATEWAY_DENIED_IPS=172.1.0.1,172.1.0.2
+# GATEWAY_USERS="user1:password1,user2:password2"
 GATEWAY_ALLOWED_IPS=
 GATEWAY_DENIED_IPS=
 GATEWAY_USERS=
-GATEWAY_FASTCGI_HTTPS=
+
+# https and reverse proxy (on/off)
+# set to on in the case : https behind a proxy
+# @run
+GATEWAY_FASTCGI_HTTPS=off
 
 # --- RabbitMQ settings ------------------------------------------------------------------------------------------------