```ruby
class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception
end
```

Add helpers and before_action for ApplicationController
user
```ruby
# frozen_string_literal: true
class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception

  helper_method :current_user, :logged_in?

  before_action :authenticate_user!

  private

  def authenticate_user!
    redirect_to login_path unless logged_in?
  end

  def current_user
    @current_user ||= User.find_by(id: session[:user_id])
  end

  def logged_in?
    !current_user.nil?
  end
end
```
assistant