The Devise Gem makes it really easy to create a full authentication app with Ruby on Rails. In the video below, I will walk you through setting up and installing the Devise Gem on your rails app. Below the video are all the commands and code that I used to create the application.

First off, we need to create our new rails application.

$ rails new devise

$ cd devise

$ mate .

Inside of your text editor, you'll want to add the devise to your 'Gemfile', which is located in the application root directory. Add the following line to the 'Gemfile':

gem 'devise'

Back in your terminal window:

$ bundle install

$ rails generate devise:install

$ rails generate devise user

$ rake db:migrate

$ rails g controller home

$ rails g controller dashboard

Inside of your '/app/controllers/home_controller.rb' file, add the following:

def index
  if user_signed_in?
    redirect_to :controller=>'dashboard', :action => 'index'
  end
end

Inside of your '/app/controllers/dashboard.rb' file, add the following:

before_filter :authenticate_user!

def index    
end

Inside of your '/app/views/home/' and '/app/views/dashboard/' directories create a new file called 'index.html.erb' and add the following code into each file:

Welcome to our Website

Welcome to your dashboard

Now, inside of your '/app/views/layouts/application.html.erb' add the following code below the opening 'body' tag:

<% if user_signed_in? %> Signed in as <%= current_user.email %>. Not you? <%= link_to "Sign out", destroy_user_session_path, :method => :delete %> <% else %> <%= link_to "Sign up", new_user_registration_path %> or <%= link_to "sign in", new_user_session_path %> <% end %>

resources :dashboard
root to: "home#index"

$ rails s