Initial pass at migrating to Capistrano 3.
Add tasks from Capistrano 3 Rails template.

Add tasks from Capistrano 3 Rails template located at
https://github.com/TalkingQuickly/capistrano-3-rails-template.git
Resolve assets precompile issue on deploy.

Resolve assets precompile issue on deploy Sprockets::FileNotFound:
couldn't find file 'twitter/bootstrap'.  Per conversation in this thread
- https://github.com/seyhunak/twitter-bootstrap-rails/issues/91 it
  appears moving the bootstrap gem out of the assets block resolves the
issue.
Remove unused Capistrano tasks.
Add capistrano/assets to compile assets.
Adds Capistrano task to copy app config files.

Adds Capistrano task setup_config to copy the application configuration
files into their production location using the command cap production
deploy:setup_config.
Merge pull request #15 from MatthewRamirez/capistrano3

Migrate to Capistrano 3 deployments