readd sessions_controller

app/controllers/sessions_controller.rb

@@ -0,0 +1,19 @@
+class SessionsController < ApplicationController
+  def create
+    if user = User.find_or_create_from_auth_hash(auth_hash)
+      session[:user_id] = user.id
+    end
+    redirect_to root_path
+  end
+
+  def destroy
+    reset_session
+    redirect_to root_path
+  end
+
+  protected
+
+  def auth_hash
+    request.env['omniauth.auth']
+  end
+end

config/routes.rb

@@ -3,6 +3,8 @@ Rails.application.routes.draw do
 
   post '/import' => 'import#new_papers_callback'
   get '/'    => 'search#index', as: :search
+  
+  resource :session, only: [:create, :destroy]
 
   # Example of regular route:
   #   get 'products/:id' => 'catalog#view'