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

  private
    def current_user
      @current_user ||= User.find(session[:user_id]) if session[:user_id]
    end
end
```

Add helper_method alias to :current_user method in AppController.
user
```ruby
class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception

  private
    def current_user
      @current_user ||= User.find(session[:user_id]) if session[:user_id]
    end

  helper_method :current_user
end
```
assistant