* Wrap user/identity coupled logic in a transaction
Creating a user and then setting an identiy should occur as an all-or-nothing step.
Wrapping this in an ActiveRecord::Transaction ensures that we don't update an identity
unless we succesfully create/update the user first in the same database transaction.
* Allow errors from authenticator service to bubble up
* Address some issues with logic in ActiveRecord::Base.transaction
* Pull out calls to DataDog from transaction.
* Add additional DataDog call in case something goes wrong in the transaction.
* Rename some methods, add some specs.
* Re-raise errors after notifying DataDog
* Add error message to DataDog tags in Authenticator
* Add Authentication providers
* Making strides on refactoring
* New usr from Twitter
* Existing Twitter user
* Existing user Github
* Test skip_confirmation!
* Refactor a bit and add simplecov groups
* Test user already logged in
* Rename to Authentication::Authenticator
* Refactor to a common class
* Add existing user test for twitter login
* Refactor global handler
* Fix spec and comment Twitter provider
* Update comments and strategy TODO
* Move providers loading code to Authentication::Providers
* add SubclassResponsibility error
* Use delegation
