devise.md

rails generate devise:install
rails rails generate devise MODEL
rake db:migrate
rails generate devise:views
rails generate devise:controllers [scope]

you need to set up the default URL options for the Devise mailer in each environment. Here is a possible configuration for config/environments/development.rb:

config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }

class ApplicationController < ActionController::Base
  before_action :configure_permitted_parameters, if: :devise_controller?

  protected

  def configure_permitted_parameters
    devise_parameter_sanitizer.for(:sign_up) << :username
  end
end

devise_for :users
 
authenticated :user do
  root to: "home#index", as: :authenticated_root
end 
unauthenticated do
  root to: "mine#profile", as: :unauthenticated_root
end

https://github.com/plamena/devise_nested_form

caok/devise.md