Add configuration for Disqus comments

Vapor version 1.4 makes it much easier to enable Disqus comments. In the past, I had to add code to the theme. Glad to see this changed, making it easy to uncomment in a couple of places and fill in my username. The only weird issue that I've had in previous and current version is with invalid redirections.

When I click on my name at the bottom of a post, it's supposed to redirect to my homepage, however, it doesn't do it right. An example URL is:

`http://www.jamesejr.com/mcafee-second-hand-device-research-project/www.jamesejr.com`

I imagine it's related to my custom domain settings in Ghost. I listed my domain as `www.jamesejr.com` instead of `http://www.jamesejr.com`. I'm sure that is the issue, but it shouldn't be. Maybe in the future I'll dig into this and submit a pull request to the project maintainer. By default, it should fill the correct URL since Ghost doesn't care if you enter your custom domain with the leading `http://` or not.