added ping to the container - useful tool

Dockerfile

@@ -4,6 +4,8 @@ USER 1001
 
 CMD mkdir -p /config /var/www/olivetin/
 
+CMD dnf install -y iputils && dnf clean all && rm -rf /var/cache/yum # install ping
+
 EXPOSE 1337/tcp 
 EXPOSE 1338/tcp 
 EXPOSE 1339/tcp