docker: make extra hosts an env variable

Author: ffreddow

docker/.env.example

@@ -18,3 +18,5 @@ SERVICEDOMAIN=
 EMAIL=
 
 IS_SEB=
+
+EXTRA_HOSTS=

docker/docker-compose.yml

@@ -63,6 +63,8 @@ services:
       - SENDER_EMAIL=${SENDER_EMAIL}
       - SENDER_NAME=${SENDER_NAME}
       - BRAND=${BRAND}
+    extra_hosts:
+      - "${EXTRA_HOSTS}"
     healthcheck:
       test: ["CMD", "curl", "backend:8081"]
       interval: 20s