Installation

Devise 4.0 works with Rails 4.1 onwards. Add the following line to your Gemfile:

gem 'devise'

Then run bundle install

Next, you need to run the generator:

$ rails generate devise:install

At this point, a number of instructions will appear in the console. Among these instructions, you'll 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 }

The generator will install an initializer which describes ALL of Devise's configuration options. It is imperative that you take a look at it. When you are done, you are ready to add Devise to any of your models using the generator.

In the following command you will replace MODEL with the class name used for the application’s users (it’s frequently User but could also be Admin). This will create a model (if one does not exist) and configure it with the default Devise modules. The generator also configures your config/routes.rb file to point to the Devise controller.

$ rails generate devise MODEL

Next, check the MODEL for any additional configuration options you might want to add, such as confirmable or lockable. If you add an option, be sure to inspect the migration file (created by the generator if your ORM supports them) and uncomment the appropriate section. For example, if you add the confirmable option in the model, you'll need to uncomment the Confirmable section in the migration.

Then run rails db:migrate

You should restart your application after changing Devise's configuration options (this includes stopping spring). Otherwise, you will run into strange errors, for example, users being unable to login and route helpers being undefined.