Send devise emails async

Gemfile

@@ -16,6 +16,7 @@ gem "pg", group: :postgres
 # Auth
 gem "devise", '~> 2.2'
+gem "devise-async"
 gem 'omniauth', "~> 1.1.3"
 gem 'omniauth-google-oauth2'
 gem 'omniauth-twitter'

Gemfile.lock

@@ -106,6 +106,8 @@ GEM
       orm_adapter (~> 0.1)
       railties (~> 3.1)
       warden (~> 1.2.1)
+    devise-async (0.8.0)
+      devise (>= 2.2, < 3.2)
     diff-lcs (1.2.4)
     dotenv (0.8.0)
     email_spec (1.4.0)
@@ -564,6 +566,7 @@ DEPENDENCIES
   d3_rails (~> 3.1.4)
   database_cleaner
   devise (~> 2.2)
+  devise-async
   email_spec
   enumerize
   factory_girl_rails

app/models/user.rb

@@ -42,8 +42,8 @@ require 'carrierwave/orm/activerecord'
 require 'file_size_validator'
 class User < ActiveRecord::Base
-  devise :database_authenticatable, :token_authenticatable, :lockable,
-         :recoverable, :rememberable, :trackable, :validatable, :omniauthable, :registerable
+  devise :database_authenticatable, :token_authenticatable, :lockable, :async,
+         :recoverable, :rememberable, :trackable, :validatable, :omniauthable
   attr_accessible :email, :password, :password_confirmation, :remember_me, :bio, :name, :username,
                   :skype, :linkedin, :twitter, :color_scheme_id, :theme_id, :force_random_password,

config/initializers/devise_async.rb

+Devise::Async.backend = :sidekiq