First working version with devise+rails_admin

app/assets/stylesheets/pages.scss

@@ -0,0 +1,3 @@
+// Place all the styles related to the pages controller here.
+// They will automatically be included in application.css.
+// You can use Sass (SCSS) here: https://sass-lang.com/

app/controllers/pages_controller.rb

@@ -0,0 +1,4 @@
+class PagesController < ApplicationController
+  def home
+  end
+end

app/helpers/pages_helper.rb

@@ -0,0 +1,2 @@
+module PagesHelper
+end

app/javascript/packs/application.js

@@ -7,7 +7,8 @@ require("@rails/ujs").start()
 require("turbolinks").start()
 require("@rails/activestorage").start()
 require("channels")
-
+global.toastr = require("toastr")
+import "../stylesheets/application"
 
 // Uncomment to copy all static images under ../images to the output folder and reference
 // them with the image_pack_tag helper in views (e.g <%= image_pack_tag 'rails.png' %>)

app/javascript/stylesheets/application.scss

@@ -0,0 +1 @@
+@import 'toastr'

app/models/admin.rb

@@ -2,5 +2,6 @@ class Admin < ApplicationRecord
   # Include default devise modules. Others available are:
   # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
   devise :database_authenticatable, :registerable,
-         :recoverable, :rememberable, :validatable
+         :recoverable, :rememberable, :validatable, :confirmable,
+         :lockable, :timeoutable, :trackable, :omniauthable
 end

app/views/layouts/application.html.erb

@@ -10,6 +10,14 @@
   </head>
 
   <body>
+  <% unless flash.empty? %>
+    <script type="text/javascript">
+        <% flash.each do |f| %>
+        <% type = f[0].to_s.gsub('alert', 'error').gsub('notice', 'info') %>
+        toastr['<%= type %>']('<%= f[1] %>');
+        <% end %>
+    </script>
+  <% end %>
     <p class="notice"><%= notice %></p>
     <p class="alert"><%= alert %></p>
     <%= yield %>

app/views/pages/home.html.erb

@@ -0,0 +1,2 @@
+<h1>Pages#home</h1>
+<p>Find me in app/views/pages/home.html.erb</p>