Configure omniauth logger to use Rails logger
Fix omniauth routes, give alias
Re-add facebook signin button to signin page
Fix to button tag on signin page
Downgrade Gem omniauth-facebook to 1.4.0

Version > 1.4.0 has issues with CSRF, see https://github.com/mkdynamic/omniauth-facebook/issues/73
Refactor formatting of sessions#new template
Add option to merge new identity to existing user