include twitter and omniauth gems, set up routes for omniauth
add dotenv gem, .env file, and include in .gitignore
create sessions controller
make create_with_omniauth method in Poet model
modify view to have basic sign in, sign out links and add current user method in application controller
remove methods current user methods in Application controller, create logged_in? method in Application helper
replace omniauth gem with omniauth-twitter gem
remove oauth_token and oauth_poets from poets table, add provider and uid in poets table, fix simple bugs in session controller, and application helper
merge with master, resolve merge conflict'