How to set the Default Page in Rails 5

Steps

Step 1: Add a root route

Open the file config/routes.rb in an editor (eg NotePad++)

Look for the line Rails.application.routes.draw at the beginning of the file, and add the line root 'topics#index' after it. When you are done the start of the file should look like this:

Rails.application.routes.draw do
  root 'topics#index'

Step 2: Confirm your changes

Go back to http://localhost:3000/. You should be taken to the topics list automatically.

More at http://docs.railsbridge.org/intro-to-rails/setting_the_default_page