fix var for port

compose.yml

@@ -187,10 +187,9 @@ services:
     volumes:
       - ./files/icinga2:/data
     ports:
-      - ${ICINGA_API_PORT:5665}:5665  # only need if you plan to use api from other sources as icingaweb2
+      - ${ICINGA_API_PORT:-5665}:5665  # only need if you plan to use api from other sources as icingaweb2
     networks:
       - icinga
-      #- backend
     environment:
       # REMOVE VARS HERE IF YOU EDIT THE CONFIG DIRECTLY!! 
       # The variables are primarily for the initial setup, later editing is recommended directly in the icinga config.