set env vars default values in docker-compose

docker-compose.yml

@@ -7,16 +7,16 @@ services:
       context: ./
       args:
         source_repository: "https://github.com/faircoin/faircoin.git"
-        RUNNER_UID: "${RUNNER_UID}"
-        RUNNER_GID: "${RUNNER_GID}"
-        FAIRCOIN_PORT: ${FAIRCOIN_PORT}
+        RUNNER_UID: "${RUNNER_UID:-1000}"
+        RUNNER_GID: "${RUNNER_GID:-1000}"
+        FAIRCOIN_PORT: ${FAIRCOIN_PORT:-40404}
     env_file:
       - ${FAIRCOIN_CONF}
     container_name: FairCoin.Co-faircoind
     restart: always
-    command: '-disablewallet -port=${FAIRCOIN_PORT} -blocknotify=/home/faircoin/script/blocknotify.sh'
+    command: '-disablewallet -port=${FAIRCOIN_PORT:-40404} -blocknotify=/home/faircoin/script/blocknotify.sh'
     network_mode: "host"
-    user: "${RUNNER_UID}:${RUNNER_GID}"
+    user: "${RUNNER_UID:-1000}:${RUNNER_GID:-1000}"
     volumes:
       - ~/.faircoin2:/home/faircoin/.faircoin2
       - ./script:/home/faircoin/script