Skeleton for updating Playlist with content

  * Update integration test to go through first use case
  * Playlists get instantiated, remove class method to update playlist
  * Define Billboard to retrieve songs from Billboard charts
Create simple Admin section

  * Supports authorization with YouTube
  * Add initializers for application admin credentials and YouTube user
    credentials
  * Also, update playlist.css to be specific to playlist elements
Add support for flash messages

Taken from https://gist.github.com/roberto/3344628
Add admin section to get YouTube refresh token

After clicking link to get authorization, user will be redirected to
YouTube/Google to give the application access to the user's data

YouTube/Google will redirect to application and refresh token will displayed in
flash message

Refresh token must be saved in local environment variable; environment variable
is loaded into application through an intializer
Refactor google-api-ruby-client interface

  * Split up responsiblites into separate classes
  * Also update YoutubeAuthorizationsController with changes to interface
Fold Youtube::Authorization into Youtube::Client
Retrieve access token when getting authorization

  * Need both refresh token and access token to regain authorization after
    access token has expired
  * Also use new Youtube::Client
Remove access token, don't need to store it
Add ablility to recreate Youtube access token
Create playlist on YouTube and populate with songs
Use VCR to stub external web requests in tests

  * Also mark some tests as pending