Update Dockerfile

Dockerfile

@@ -20,9 +20,10 @@ WORKDIR /var/www/html
 RUN chown -R www-data:www-data /var/www/html \
     && chmod -R 755 /var/www/html
 
-RUN echo "Listen 7860" >> /etc/apache2/ports.conf
+RUN echo "ServerName localhost" >> /etc/apache2/apache2.conf
 
-RUN sed -i 's/<VirtualHost \*:80>/<VirtualHost \*:7860>/' /etc/apache2/sites-available/000-default.conf
+RUN sed -i 's/Listen 80/Listen 7860/' /etc/apache2/ports.conf \
+    && sed -i 's/<VirtualHost \*:80>/<VirtualHost \*:7860>/' /etc/apache2/sites-available/000-default.conf
 
 EXPOSE 7860