Updating repo to newest version of Phoenix

[Faheetah]

I know your work on couchdb is on maintenance mode and you might not care as much about this PR, but I found your blog post helpful and figured I would take a crack at upgrading the dependencies to something more modern. Both mix phx.server and mix test work as expected. Most changes are either renaming to the new convention as BirdWatchWeb or updating to mix format. Putting in a PR in case you find this helpful. I'd be interested in taking a crack at couchdb_connector too since it is throwing a lot of warnings now, but it seems to be pretty much the couchdb library these days.

I also wouldn't care if this got closed too, it at least gives a paper trail from other people having issues running it on the newer version of Elixir/Phoenix.