Send emails via sidekiq (#380)

* add sidekiq web view if the user is an administrator

* add sidekiq setup configuration and support

* update devise to use delivery_later method and update test

* update conversation to use deliver_later instead of deliver

* Update Routes

* Add Procfile for Heroku One-Click Start

* updating docs

* update concurrency and Procfile for supporting Heroku Free Dyno

* update Procfile.dev

config/environments/development.rb

@@ -33,6 +33,8 @@ Rails.application.configure do
   config.active_storage.service = :local
 
   # Don't care if the mailer can't send.
+  config.active_job.queue_adapter = :sidekiq
+  
   config.action_mailer.raise_delivery_errors = false
 
   config.action_mailer.perform_caching = false

config/environments/production.rb

@@ -75,6 +75,7 @@ Rails.application.configure do
   # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
   # the I18n.default_locale when a translation cannot be found).
   config.i18n.fallbacks = true
+  config.active_job.queue_adapter = :sidekiq
 
   # Send deprecation notices to registered listeners.
   config.active_support.deprecation = :notify

config/environments/staging.rb

@@ -75,6 +75,7 @@ Rails.application.configure do
   # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
   # the I18n.default_locale when a translation cannot be found).
   config.i18n.fallbacks = true
+  config.active_job.queue_adapter = :sidekiq
 
   # Send deprecation notices to registered listeners.
   config.active_support.deprecation = :notify

config/environments/test.rb

@@ -43,6 +43,7 @@ Rails.application.configure do
   # The :test delivery method accumulates sent emails in the
   # ActionMailer::Base.deliveries array.
   config.action_mailer.delivery_method = :test
+  config.active_job.queue_adapter = :test
 
   # Print deprecation notices to the stderr.
   config.active_support.deprecation = :stderr

config/routes.rb

@@ -90,6 +90,12 @@ Rails.application.routes.draw do
     end
   end
 
+  # Sidekiq Web UI
+  require 'sidekiq/web'
+  authenticate :user, lambda { |u| u.administrator? } do
+    mount Sidekiq::Web => '/sidekiq'
+  end
+
   # Used in mailer templates
   resource :app, only: [:index] do
     resources :conversations, only: [:show]

config/sidekiq.yml

@@ -0,0 +1,23 @@
+# Sample configuration file for Sidekiq.
+# Options here can still be overridden by cmd line args.
+# Place this file at config/sidekiq.yml and Sidekiq will
+# pick it up automatically.
+---
+:verbose: false
+:concurrency: 10
+:timeout: 25
+
+# Sidekiq will run this file through ERB when reading it so you can
+# even put in dynamic logic, like a host-specific queue.
+# http://www.mikeperham.com/2013/11/13/advanced-sidekiq-host-specific-queues/
+:queues:
+  - critical
+  - default
+  - low
+  - mailers
+
+# you can override concurrency based on environment
+production:
+  :concurrency: 3
+staging:
+  :concurrency: 15