Add frozen string literal to files.

Gemfile

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source 'https://rubygems.org'
 
 group :development do

app/controllers/house_ad_settings_controller.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ::AdPlugin
   class HouseAdSettingsController < ::ApplicationController
     requires_plugin AdPlugin.plugin_name

app/controllers/house_ads_controller.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ::AdPlugin
   class HouseAdsController < ::ApplicationController
     requires_plugin AdPlugin.plugin_name

app/models/house_ad.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ::AdPlugin
   class HouseAd
     include ActiveModel::Validations

app/models/house_ad_setting.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ::AdPlugin
   class HouseAdSetting
     DEFAULTS = {

bin/pull_translations.rb

@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
 
 # Usage:
 #   bundle install

plugin.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # name: discourse-adplugin
 # about: Ad Plugin for Discourse
 # version: 1.2.0

spec/models/house_ad_setting_spec.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails_helper'
 
 describe AdPlugin::HouseAdSetting do

spec/models/house_ad_spec.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails_helper'
 
 describe AdPlugin::HouseAd do
@@ -117,7 +119,7 @@ describe AdPlugin::HouseAd do
     end
 
     it "validates attributes" do
-      ad = AdPlugin::HouseAd.create({name: '', html: ''})
+      ad = AdPlugin::HouseAd.create(name: '', html: '')
       expect(ad).to be_a(AdPlugin::HouseAd)
       expect(ad).to_not be_valid
       expect(ad.errors.full_messages).to be_present

spec/requests/house_ad_settings_controller_spec.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails_helper'
 
 describe AdPlugin::HouseAdSettingsController do