add comments, add configurable JAVA_OPTS

docker-compose.yml

@@ -6,8 +6,10 @@ services:
     container_name: "mindustry_server"
     hostname: "mindustry-server"
     ports:
-      - "6567:6567/tcp"
+      - "6567:6567/tcp" #host-port:internal-port
       - "6567:6567/udp"
+    environment:
+      - "JAVA_OPTS=-Xms1G -Xmx2G" #set memory limits
     tty: true
     stdin_open: true
     restart: always

entrypoint.sh

@@ -3,4 +3,5 @@
 chown mindustry:mindustry -R ~mindustry
 
 # run server as non-elevated user
-su mindustry bash -c 'java -jar -Xms1G -Xmx2G /usr/local/share/mindustry/server.jar host'
+su mindustry bash -c 'export JAVA_OPTS="'"$JAVA_OPTS"'"; 
+                     java -jar /usr/local/share/mindustry/server.jar host'