Enable soft_deletion of Banner::Translations

Also create missing banner model spec.

db/migrate/20190122133850_add_hidden_at_to_banner_translations.rb

@@ -0,0 +1,6 @@
+class AddHiddenAtToBannerTranslations < ActiveRecord::Migration[4.2]
+  def change
+    add_column :banner_translations, :hidden_at, :datetime
+    add_index :banner_translations, :hidden_at
+  end
+end

db/schema.rb

@@ -98,7 +98,9 @@ ActiveRecord::Schema.define(version: 20190607160900) do
     t.datetime "updated_at",  null: false
     t.string   "title"
     t.text     "description"
+    t.datetime "hidden_at"
     t.index ["banner_id"], name: "index_banner_translations_on_banner_id", using: :btree
+    t.index ["hidden_at"], name: "index_banner_translations_on_hidden_at", using: :btree
     t.index ["locale"], name: "index_banner_translations_on_locale", using: :btree
   end
 

spec/models/banner_spec.rb

@@ -0,0 +1,15 @@
+require "rails_helper"
+
+describe Banner do
+
+  let(:banner) { build(:banner) }
+
+  describe "Concerns" do
+    it_behaves_like "acts as paranoid", :banner
+  end
+
+  it "is valid" do
+    expect(banner).to be_valid
+  end
+
+end