Update Dockerfile

Dockerfile

@@ -16,7 +16,8 @@ RUN apt-get update \
     && apt-get install -y curl \
     && apt-get install -y jq \
     && rm -rf /var/lib/apt/lists/* \
-    && mkdir /papermc 
+    && mkdir /papermc \
+    && groupadd -r mcuser && useradd -r -g mcuser mcuser
 
 # Start script