option to change the port of the webserver

Dockerfile

@@ -11,6 +11,9 @@ ARG DEBIAN_FRONTEND="noninteractive"
 
 ENV NVM_DIR="/root/.nvm"
 
+# port to for the webserver
+ENV WEBSERVER_PORT=8080
+
 COPY start-container.sh /usr/local/bin/start-container
 
 RUN apt-get -y update \
@@ -33,7 +36,7 @@ RUN apt-get -y update \
     && nvm install $NODE_VERSION \
     && nvm alias default $NODE_VERSION;
 
-EXPOSE 8080
+EXPOSE ${WEBSERVER_PORT}
 
 WORKDIR /var/www/html