Added .vagrant/ and Berksfile.lock to .gitignore

1. I added .vagrant/ to .gitignore.

2. I am unsure about this: Added Berksfile.lock to .gitignore. It seems that chef-dokku is set up like a single cookbook that can be used in an application (with many cookbooks; sorry, I don't fully know chef terminologies yet). So like with Gemfile.lock, should Berksfile.lock be ignored since this repo is like a "Gem" and not like an "application"? Or is chef-dokku considered an "application"?

Thanks!