FIX: when ensuring consistency also delete orphan badges

app/models/badge.rb

@@ -374,6 +374,13 @@ SQL
   end
 
   def self.ensure_consistency!
+    exec_sql <<SQL
+    DELETE FROM user_badges
+    USING user_badges ub
+    LEFT JOIN users u ON u.id = ub.user_id
+    WHERE u.id IS NULL
+SQL
+
     Badge.find_each(&:reset_grant_count!)
   end
 

spec/models/badge_spec.rb

@@ -43,5 +43,18 @@ describe Badge do
     expect(badge[:long_description]).to eq("testing it")
   end
 
+  it 'can ensure consistency' do
+    b = Badge.first
+    b.grant_count = 100
+    b.save
+
+    UserBadge.create!(user_id: -100, badge_id: b.id, granted_at: 1.minute.ago, granted_by_id: -1)
+
+    Badge.ensure_consistency!
+
+    b.reload
+    expect(b.grant_count).to eq(0)
+  end
+
 end