📝 Writing docs. 优化 dockerfile

pigx-register/Dockerfile

@@ -12,4 +12,4 @@ EXPOSE 8848
 
 ENV TZ=Asia/Shanghai JAVA_OPTS="-Xms128m -Xmx256m -Djava.security.egd=file:/dev/./urandom"
 
-CMD sleep 30; java -jar app.jar $JAVA_OPTS
+CMD sleep 30; java $JAVA_OPTS -jar app.jar