HOW TO USE DEVISE GEM

$ rails new devise_app -j esbuild -css bootstrap

$ cd devise_app

$ bundle add devise

$ rails g devise:install

$ rails g devise User

$ rails g controller pages home

$ rails db:migrate

[config/routes.rb]
root 'pages#home'

[app/views/pages/home.html.erb]

<% if current_user %>
    <p>Logged in as <%= current_user.email %></p>
    <%= link_to "Logout", destroy_user_session_path, method: :delete, data: { turbo_method: :delete } %>
<% else %>
    <%= link_to "Login", new_user_session_path %>
    <%= link_to "Sign up", new_user_registration_path %>
<% end %>

🐞Source: devise