How to generate CSV in rails

How to generate csv and fetching the data from xls/fetching from db are given below,

users = User.first 10
file = “#{Rails.root}/public/user_data.csv”
column_headers = [“User ID”, “First Name”, “Last Name”, “Email”]
CSV.open(file, ‘w’, write_headers: true, headers: column_headers) do |writer|
users.each do |user|
writer << [user.id, user.login, user.name, user.email]
end
end