Ruby -

Installing Ruby on Rails

Install a Ruby version manager.

# Install Homebrew if you don't have it.
brew update
brew install rbenv ruby-build

rbenv install -l
rbenv install 2.2.2 # Or whatever Heroku currently supports
rbenv global 2.2.2  # Ruby version used if project doesn't have version defined

Install Ruby on Rails.

gem install bundler
gem install rails

# if you get a SSL error:
gem update --system
gem update bundler
# if doesn't help, try:
gem sources
gem sources -r https://rubygems.org/
gem sources -a http://rubygems.org/

Check that Ruby on Rails works.

rails new ruby-blog
cd ruby-blog
rbenv local 2.2.2 # Defines Ruby version for this project
bundle install
bin/rails server
# => http://localhost:3000/

rails generate controller welcome index
# => app/controllers/welcome_controller.rb
# => app/views/welcome/index.html.erb

# after changing Gemfile
bundle install

Some useful commands.

# Recompile assets so the are ready for production.
RAILS_ENV=production bundle exec rake assets:precompile