Add attribute Account#guest_token

app/models/account.rb

@@ -13,6 +13,10 @@ class Account < ApplicationRecord
 
   scope :guests, -> { includes(:user).where(users: { id: nil }) }
 
+  before_create do
+    self.guest_token = SecureRandom.hex
+  end
+
   def guest?
     user.nil?
   end

db/migrate/20181210024922_add_guest_token_to_accounts.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class AddGuestTokenToAccounts < ActiveRecord::Migration[5.2]
+  def change
+    add_column :accounts, :guest_token, :string,
+               null:  false, # rubocop:disable Rails/NotNullColumn
+               index: { unique: true }
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2018_12_07_030332) do
+ActiveRecord::Schema.define(version: 2018_12_10_024922) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -28,6 +28,7 @@ ActiveRecord::Schema.define(version: 2018_12_07_030332) do
   create_table "accounts", force: :cascade do |t|
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.string "guest_token", null: false
   end
 
   create_table "active_storage_attachments", force: :cascade do |t|