Add an IP bind param to the entrypoint (#447)

* Add an IP bind param to the entrypoint

* Add an example usage to readme

* Rename to BIND

docker/docker-compose.yml

@@ -20,3 +20,4 @@ services:
 #      - USERNAME=FactorioUsername
 #      - TOKEN=FactorioToken
 #      - PORT=34198
+#      - ADDR=::1

docker/files/docker-entrypoint.sh

@@ -5,6 +5,7 @@ FACTORIO_VOL=/factorio
 LOAD_LATEST_SAVE="${LOAD_LATEST_SAVE:-true}"
 GENERATE_NEW_SAVE="${GENERATE_NEW_SAVE:-false}"
 SAVE_NAME="${SAVE_NAME:-""}"
+BIND="${BIND:-""}"
 
 mkdir -p "$FACTORIO_VOL"
 mkdir -p "$SAVES"
@@ -88,6 +89,10 @@ FLAGS=(\
   --server-id /factorio/config/server-id.json \
 )
 
+if [ -n "$BIND" ]; then
+  FLAGS+=( --bind "$BIND" )
+fi
+
 if [[ $LOAD_LATEST_SAVE == true ]]; then
     FLAGS+=( --start-server-load-latest )
 else