added gems for authentication

added devise
omniauth
omniauth-twitter
uuidtools
update of the Gemfile.lock after running bundle install
added dev default url, root route and the flash messages in the application.html.erb

Ran the rails generate devise:install
And I got the following error message.

The steps are meant to counter the issues raised.

create  config/initializers/devise.rb
      create  config/locales/devise.en.yml
========================================================================
=======

Some setup you must do manually if you haven't yet:

  1. Ensure you have defined default url options in your environments
files. Here
     is an example of default_url_options appropriate for a development
environment
     in config/environments/development.rb:

       config.action_mailer.default_url_options = { :host =>
'localhost:3000' }

     In production, :host should be set to the actual host of your
application.

  2. Ensure you have defined root_url to *something* in your
config/routes.rb.
     For example:

       root :to => "home#index"

  3. Ensure you have flash messages in
app/views/layouts/application.html.erb.
     For example:

       <p class="notice"><%= notice %></p>
       <p class="alert"><%= alert %></p>

  4. If you are deploying on Heroku with Rails 3.2 only, you may want
to set:

       config.assets.initialize_on_precompile = false

     On config/application.rb forcing your application to not access
the DB
     or load models when precompiling your assets.

  5. You can copy Devise views (for customization) to your app by
running:

       rails g devise:views

========================================================================
=======
executed rails generate devise user

the results of

rails generate devise user
executed `rails generate model authorization`
added the name

according to the location 213 of the ebook, we just add the name
executed rake db:migrate
Make Authorization model belongs to user
add twitter consumer key and secret to the initializers/devise.rb
moved the secret and the key to the app_config.yml
created new omniauthcallbackscontroller to handle twitter callbacks
add omniauth_callbacks option to the routes
User model has_many Authorizations
add twitter method code to handle callbacks from twitter