Container uses Django development webserver

[zicklag]

I noticed that this container uses the out-of-the-box Django webserver instead of using a dedicated web server. According to the Django documentation:

Don’t use this server in anything resembling a production environment. It’s intended only for use while developing. (We’re in the business of making Web frameworks, not Web servers.)

The Taiga documentation suggests installing it with a Gunicorn webserver. It seems that it would be best to do something like that instead of using the development server. I am using this container in production, so I would rather have a production quality webserver. If @benhutchins agrees with using Gunicorn I may try to install it and make a pull request for it.

[benhutchins]

I definitely agree and will be merging #43 as soon as I verify it works