add user authentication before filter
begin devise omniauth configure
configure devise login/logout, connect devise views, add omniauth gem, add dotenv gem, add facebook app credentials to environment
bundle devise and facebook/omniauth gems, require omniauth-facebook gem in config
add .env file to git ignore way after the fact like an idiot
generate omniauth callbacks controller for handling facebook auth; adjust inheritance path
create callback method for callbacks controller, facebook strategy; configure route file for callbacks controller