Destroy dashboard query when query is deleted

app/models/blazer/query.rb

@@ -2,6 +2,7 @@ module Blazer
   class Query < ActiveRecord::Base
     belongs_to :creator, class_name: Blazer.user_class.to_s if Blazer.user_class
     has_many :checks, dependent: :destroy
+    has_many :dashboard_queries, dependent: :destroy
 
     validates :name, presence: true
     validates :statement, presence: true