Add: #581 NGワード検出履歴を定期的に削除する処理 (#619)

* Add: #581 NGワード検出履歴を定期的に削除する処理

* マイグレーションコードを修正

spec/lib/vacuum/ng_histories_vacuum_spec.rb

@@ -6,6 +6,8 @@ RSpec.describe Vacuum::NgHistoriesVacuum do
   subject { described_class.new }
 
   describe '#perform' do
+    let!(:word_history_old) { Fabricate(:ngword_history, created_at: 30.days.ago) }
+    let!(:word_history_recent) { Fabricate(:ngword_history, created_at: 2.days.ago) }
     let!(:rule_history_old) { Fabricate(:ng_rule_history, created_at: 30.days.ago) }
     let!(:rule_history_recent) { Fabricate(:ng_rule_history, created_at: 2.days.ago) }
 
@@ -14,10 +16,12 @@ RSpec.describe Vacuum::NgHistoriesVacuum do
     end
 
     it 'deletes old history' do
+      expect { word_history_old.reload }.to raise_error ActiveRecord::RecordNotFound
       expect { rule_history_old.reload }.to raise_error ActiveRecord::RecordNotFound
     end
 
     it 'does not delete recent history' do
+      expect { word_history_recent.reload }.to_not raise_error
       expect { rule_history_recent.reload }.to_not raise_error
     end
   end