Quickly setup a ruby on rails edge app

Setup your app directory

mkdir rails-edge-test-app
cd rails-ege-test-app

Specify your Ruby version

touch .ruby-version
echo 'ruby-2.3.1' > .ruby-version

Setup Gemfile with edge rails, rack and arel

touch Gemfile
printf "source 'https://rubygems.org'\nruby '2.3.1'\n\n\ngem 'rails', github: 'rails/rails'" >> Gemfile
bundle

Use rails generators to create new app, and run server

bundle exec rails new . --dev --force
bundle exec rails s