simplify reverse proxy (#98)

make use of mainline nginx image, switch ssl/non-ssl config file based on presence of cert/key, hardcode app port since it is hardcoded in the app container as well

web/Dockerfile

@@ -1,22 +1,9 @@
-FROM ubuntu:14.04
+FROM nginx:mainline
 
-RUN apt-get update && apt-get install -y nginx
-
-RUN rm /etc/nginx/sites-enabled/default
-
-COPY mattermost /etc/nginx/sites-available/
-COPY mattermost-ssl /etc/nginx/sites-available/
-ADD docker-entry.sh /
+RUN rm /etc/nginx/conf.d/default.conf
+COPY ./mattermost /etc/nginx/sites-available/
+COPY ./mattermost-ssl /etc/nginx/sites-available/
 
+COPY docker-entry.sh /
 RUN chmod +x /docker-entry.sh
-
-# You can see the logs using `docker-compose logs web`.
-RUN ln -sf /dev/stdout /var/log/nginx/access.log
-RUN ln -sf /dev/stderr /var/log/nginx/error.log
-
-# Define working directory.
-WORKDIR /etc/nginx
-
 ENTRYPOINT /docker-entry.sh
-
-EXPOSE 80 443