title: How would you refactor this
body: <p>'def show</p>
  
  <pre><code> @dept = Dept.find(params[:id])
      @members = @dept.members_list.collect{|a|a.name}
      dif = @dept.users.collect{|a|[a.name,a.id]}
      @admin_list = @dept.admin_users.collect{|a|a.user}
     @not_member_users = User.all_users - dif
     @not_admin_user = (@dept.list_of_deptmembers - @dept.admin_users).collect{|a|[a.user.name, a.id]}'    
  </code></pre>
  
  <p>how can i refactor the @not_admin_user??</p>