Update Dockerfile

Dockerfile

@@ -55,6 +55,8 @@ RUN \
   ln -s /config/proxy-config.conf /etc/apache2/sites-available/000-default.conf && \
   ln -s /var/log/apache2 /logs && \
   ln -s -v /web /var/www
+  
+RUN mkdir /etc/apache2/sites-available/
 
 # Generate ossn conf files
 RUN echo \