If you've already installed devise into your app, and want to add "confirmable" later, instead of running:
rails generate devise:views
as mentioned by Piotr, run
rails generate devise:views confirmable
to produce only the views needed for "confirmable". You'll see output like this:
rails generate devise:views confirmable
invoke Devise::Generators::SharedViewsGenerator
create app/views/confirmable/mailer
create app/views/confirmable/mailer/confirmation_instructions.html.erb
create app/views/confirmable/mailer/reset_password_instructions.html.erb
create app/views/confirmable/mailer/unlock_instructions.html.erb
create app/views/confirmable/shared
create app/views/confirmable/shared/_links.erb
invoke form_for
create app/views/confirmable/confirmations
create app/views/confirmable/confirmations/new.html.erb
create app/views/confirmable/passwords
create app/views/confirmable/passwords/edit.html.erb
create app/views/confirmable/passwords/new.html.erb
create app/views/confirmable/registrations
create app/views/confirmable/registrations/edit.html.erb
create app/views/confirmable/registrations/new.html.erb
create app/views/confirmable/sessions
create app/views/confirmable/sessions/new.html.erb
create app/views/confirmable/unlocks
create app/views/confirmable/unlocks/new.html.erb
You'll then be able to access these files directly in your project to style them like your application. You'll also be able to change the messaging in the emails Devise sends out through the generated mailer views.
Last, don't forget to add config.action_mailer.delivery_method and config.action_mailer.smtp_settings in your app/config/environments/{environment_name}.rb file. This is what my production.rb file looks like:
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
:address => "smtp.gmail.com",
:port => 587,
:domain => '[redacted]',
:user_name => '[redacted]',
:password => '[redacted]',
:authentication => 'plain',
:enable_starttls_auto => true }