Omniauth facebook without devise

- Added omniauth and omniauth-facebook gem
- created config/initializers/omniauth.rb
- Created signuper app on facebook developer platform
- Added "http://localhost:3000" to signuper facebook app platform
- Inserted facebook JavascriptSDK into index page
- input facebook APP_ID and APP_SECRET in .env file
- .gitignore .env file
- using /auth/facebook to request authentiation
- using /auth/facebook/callback to callback to signuper
well, actually, the way my user authentication is structured now, a password doesn't exist anymore. A user is authenticated by this method `User.find_by_provider_and_uid(auth["provider"], auth["uid"])`; so basically, user login this site by logging in facebook and then passing in their "uid" to the auth object to authenticate themselves against my site.  Is this gonna be a problem?