title: Unscope a default scope by joins asociation
body: <pre><code>class House
    has_many :items
  end
  
  class Item
    belongs_to :house
    default_scope { joins(:house}.where.not("house.status": deleted) }
  end
  </code></pre>
  
  <p>i want to know how to unscope <code>where.not("houses.status": deleted)</code> when i call <code>House.first.items</code> not have <code>WHERE ("houses"."status" != deleted)
  </code>
  this default_scope is important, can not remove it T.T</p>