tdd-rails-pluralsight | Learning TDD for Rails using RSpec | Application Framework library

Setup rails app, RSpec and Capybara gems. Instructor using: ruby 2.2.2 and rails 4.2.2. Instead will use rails 4.2.3 because of [devise bug](https://github.com/plataformatec/devise/issues/4186).
First line in any rails spec is require 'rails_helper'
Use BDD style wording - feature instead of describe and scenario instead of it
Inside scenario, use capybara methods to click, fill out forms, navigate etc.
Add welcome route to [routes.rb](i-rock/config/routes.rb)
Create [welcome_controller.rb](i-rock/app/controllers/welcome_controller.rb)
Define index action
Define welcome view [index.html.erb](i-rock/app/views/welcome/index.html.erb)
Add Welcome text to view.
Most important responsibility of controller - check if user is allowed to do what they’re requesting. Need a user and way to authenticate. To get started with this, will setup devise gem with default config.