Remove APT lists from image to lower its size

 Dockerfile

@@ -5,7 +5,8 @@

RUN apt-get -y update \
    && apt-get -y install wget sudo \
    && apt-get -y clean
    && apt-get -y clean \
    && rm -Rf /var/lib/apt/lists/*

RUN cd /tmp \
    && wget -O openfire.deb "https://www.igniterealtime.org/downloadServlet?filename=openfire/openfire_${OPENFIRE_VERSION}_all.deb" \