fix ActionView::Template::Error [undefined method `name` for nil:NilClass]

app/views/admin/activities/download_excel_format.xlsx.axlsx

@@ -57,6 +57,7 @@ wb.add_worksheet(name: "Activities") do |sheet|
   sheet.add_row row2, :style => example
 
   User.where(:user_name.ne => "rulingcom").each do |user|
+    next if user.member_profile.nil?
     r = [user.user_name]
     r << user.name
     sheet.add_row r