refactors Admin#name_and_email

app/models/administrator.rb

@@ -1,10 +1,6 @@
 class Administrator < ActiveRecord::Base
   belongs_to :user, touch: true
-  delegate :name, :email, to: :user
+  delegate :name, :email, :name_and_email, to: :user
 
   validates :user_id, presence: true, uniqueness: true
-
-  def name_and_email
-    "#{name} (#{email})"
-  end
 end