Rename oauth_token to refresh_token
Extract a Cryption module
Update User to use the Cryption module
Add User#oauth_token to be fetched from a YouTube::Service and cached
Update oauth to use offline access
Add YouTube::Service to fetch an updated oauth_token
Hide decryption logic from the Updater
Tidy up the factory syntax
Stub updated oauth token posts from the tests
Ensure FakeWeb is cleaned before each test
Remove uneeded parameter from the YouTube Updater