do not be root

Dockerfile

@@ -3,6 +3,9 @@ FROM buildpack-deps:stable
 ENV NGINX_VERSION nginx-1.19.2
 ENV NGINX_RTMP_MODULE_VERSION 1.2.1
 
+ADD startscript.sh /usr/sbin/startscript.sh
+ADD config /etc/nginx/
+
 RUN apt-get update && \
     apt-get install -y ca-certificates openssl libssl-dev ffmpeg && \
     apt-get clean && rm -rf /var/lib/apt/lists/* && \
@@ -38,11 +41,12 @@ RUN apt-get update && \
     mkdir /var/lock/nginx && \
     rm -rf /tmp/build && \
     ln -sf /dev/stdout /var/log/nginx/access.log && \
-    ln -sf /dev/stderr /var/log/nginx/error.log
-
-ADD startscript.sh /usr/sbin/startscript.sh
-ADD config /etc/nginx/
+    ln -sf /dev/stderr /var/log/nginx/error.log && \ 
+    useradd -r -d /var/cache/nginx/ -s /sbin/nologin -U nginx && \
+    ln -sf /usr/lib64/nginx/modules /etc/nginx/modules && \
+    chown R nginx:users /etc/nginx
 
+USER nginx:users
 
 EXPOSE 1935
 CMD ["bash", "/usr/sbin/startscript.sh"]