Global env via RUBOTY.env like Rails.env

We can now require gems for development:

  # Gemfile
  group :development do
    gem 'ruboty' # For development shell
    #.. Any gems!
  end

  group :production do
    gem 'ruboty-twitter' # For production adapter
  end
Add readme entry for Ruboty environment
Merge pull request #6 from taiki45/add-global-env

Introduce global environment configuration like `Rails.env`