Add Define The Root Path For The App as a Rails TIL

rails/define-the-root-path-for-the-app.md

@@ -0,0 +1,37 @@
+# Define The Root Path For The App
+
+The `root_path` helper that you might want to use in Rails controllers and
+views is not available by default.
+
+```ruby
+> Rails.application.routes.url_helpers.root_path
+
+ruby/3.2.2/lib/ruby/gems/3.2.0/gems/irb-1.14.0/lib/irb.rb:1285:in `full_message': undefined method `root_path' for #<Module:0x0000000106d11738> (NoMethodError)
+
+Rails.application.routes.url_helpers.root_path
+                                    ^^^^^^^^^^
+Did you mean?  logout_path
+               book_path
+```
+
+It needs to be declared in the `config/routes.rb` file with the controller
+action that it points to.
+
+```ruby
+# config/routes.rb
+Rails.application.routes.draw do
+  root 'home#index'
+end
+```
+
+Once this is defined the `root_path` will now be available with the rest of
+your URL helpers.
+
+```ruby
+better-reads(dev)> reload!
+Reloading...
+better-reads(dev)> Rails.application.routes.url_helpers.root_path
+=> "/"
+```
+
+[source](https://guides.rubyonrails.org/routing.html#using-root)