Begin work on asynchronous jobs

Gemfile

 gem 'will_paginate', '~> 3.1.0'
 gem 'bootstrap-will_paginate'
 
+# Delayed jobs
+gem 'delayed_job'
+gem 'delayed_job_active_record'
+gem 'daemons'
+
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console
   gem 'byebug', platform: :mri

Gemfile.lock

       execjs
     coffee-script-source (1.12.2)
     concurrent-ruby (1.0.5)
+    daemons (1.2.4)
+    delayed_job (4.1.3)
+      activesupport (>= 3.0, < 5.2)
+    delayed_job_active_record (4.1.2)
+      activerecord (>= 3.0, < 5.2)
+      delayed_job (>= 3.0, < 5)
     domain_name (0.5.20170404)
       unf (>= 0.0.5, < 1.0.0)
     erubis (2.7.0)
   byebug
   clipboard-rails
   coffee-rails (~> 4.2)
+  daemons
+  delayed_job
+  delayed_job_active_record
   faker
   font-awesome-sass
   haml

bin/delayed_job

+#!/usr/bin/env ruby
+
+require File.expand_path(File.join(File.dirname(__FILE__), '..', 'config', 'environment'))
+require 'delayed/command'
+Delayed::Command.new(ARGV).daemonize

config/application.rb

 
     config.i18n.load_path += Dir[Rails.root.join('config', 'locales', '**', '*.{rb,yml}')]
     config.i18n.default_locale = :nl
+
+    config.active_job.queue_adapter = :delayed_job
   end
 end

db/migrate/20170916212858_create_delayed_jobs.rb

+class CreateDelayedJobs < ActiveRecord::Migration[5.0]
+  def self.up
+    create_table :delayed_jobs, force: true do |table|
+      table.integer :priority, default: 0, null: false # Allows some jobs to jump to the front of the queue
+      table.integer :attempts, default: 0, null: false # Provides for retries, but still fail eventually.
+      table.text :handler,                 null: false # YAML-encoded string of the object that will do work
+      table.text :last_error                           # reason for last failure (See Note below)
+      table.datetime :run_at                           # When to run. Could be Time.zone.now for immediately, or sometime in the future.
+      table.datetime :locked_at                        # Set when a client is working on this object
+      table.datetime :failed_at                        # Set when all retries have failed (actually, by default, the record is deleted instead)
+      table.string :locked_by                          # Who is working on this object (if locked)
+      table.string :queue                              # The name of the queue this job is in
+      table.timestamps null: true
+    end
+
+    add_index :delayed_jobs, [:priority, :run_at], name: "delayed_jobs_priority"
+  end
+
+  def self.down
+    drop_table :delayed_jobs
+  end
+end

db/schema.rb

 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170815155155) do
+ActiveRecord::Schema.define(version: 20170916212858) do
 
   create_table "activities", force: :cascade do |t|
     t.string   "name"
     t.index ["group_id"], name: "index_activities_on_group_id"
   end
 
+  create_table "delayed_jobs", force: :cascade do |t|
+    t.integer  "priority",   default: 0, null: false
+    t.integer  "attempts",   default: 0, null: false
+    t.text     "handler",                null: false
+    t.text     "last_error"
+    t.datetime "run_at"
+    t.datetime "locked_at"
+    t.datetime "failed_at"
+    t.string   "locked_by"
+    t.string   "queue"
+    t.datetime "created_at"
+    t.datetime "updated_at"
+    t.index ["priority", "run_at"], name: "delayed_jobs_priority"
+  end
+
   create_table "groups", force: :cascade do |t|
     t.string   "name"
     t.datetime "created_at", null: false