Git Force-Push Deploy Pushes Root Instead of Build Dir

[JustinHardage]

I'm trying to push my middleman build directory to a GitHub Organization Page. This means that my GitHub repo master branch needs to get the output of a bundle exec middleman build command.

However, I haven't found any combination of options with deploy.method = :git that actually does this. I always get the root of the project - e.g. where the Gemfile lives - instead of something that GitHub Pages would recognize as a site with an index.html file.

How can I deploy to a GitHub Pages site?

#config.rb
activate :deploy do |deploy|
  deploy.method = :git
  deploy.remote   = 'https://github.com/FiercePunchStudios/deploy-test.git'
  deploy.branch   = 'master'
end

#Gemfile
source 'http://rubygems.org'
gem "middleman", "~> 3.4.0"
gem 'middleman-deploy', '~> 1.0'