```ruby
class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception
  skip_before_filter :verify_authenticity_token, :if => Proc.new { |c| c.request.format == 'application/json' }

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

end
```

Add global logged_in method to check if a user is logged in
user
```ruby
class ApplicationController < ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception
  skip_before_filter :verify_authenticity_token, :if => Proc.new { |c| c.request.format == 'application/json' }

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

  def logged_in
    return true if session[:user_id]
    false
  end

end
```
assistant