API for apps to register for push notifications

spec/fabricators/device_fabricator.rb

@@ -0,0 +1,3 @@
+Fabricator(:device) do
+  registration_id "12345678"
+end

spec/fabricators/domain_block_fabricator.rb

@@ -1,3 +1,3 @@
 Fabricator(:domain_block) do
-  domain "MyString"
+  domain "example.com"
 end

spec/models/device_spec.rb

@@ -0,0 +1,5 @@
+require 'rails_helper'
+
+RSpec.describe Device, type: :model do
+
+end