Fix bug.

app/models/site_server.rb

@@ -15,8 +15,6 @@ class SiteServer
   field :active , type: Boolean ,default: true
   field :has_certbot, type: Boolean , default: false
   field :need_update_site_ids, type: Array, default: []
-  has_many :site_server_file_backups, :autosave => true, :dependent => :destroy
-  has_many :site_server_db_backups, :autosave => true, :dependent => :destroy
   def domain_names
     if self.domain_name != ''
       [self.domain_name]