Docker for mattermost in production

1. Put cert.pem into web/cert and key-no-password.pem into web/cert/private.
2. docker-compose up -d

The settings of the servers are based on
https://github.com/mattermost/platform/blob/master/doc/install/Production-Ubuntu.md.

app/config_docker.json is based on
https://raw.githubusercontent.com/mattermost/platform/master/config/config.json.

db/Dockerfile

@@ -0,0 +1,4 @@
+FROM postgres
+ 
+ADD make_db.sh /docker-entrypoint-initdb.d/
+