Joseworks/contact_batch_email.html.erb

## contact_batch_email.html.erb
<!-- Contact batch email -->
<!DOCTYPE html>
<html>
  <head>
    <meta content='text/html; charset=UTF-8' http-equiv='Content-Type' />
  </head>
  <body>
    <div>Name: <%= @name %></div>
    <br>
    <div>Subject: <%= @subject %></div>
    <br>
    <div>Reply to: <%= @email %></div>
    <br>
    <div>Message: </div>
    <br>
     <div><p><%= @message %></p></div>
    <br>
  </body>
</html>

## contact_batch_mailer.rb
class ContactBatchMailer < ActionMailer::Base
  default from: "your_address_to_reply_to@example.com"
  def contact_batch_email(name, email, message, subject, recipient)
    @message = message
    @name = name
    @email = email
    @subject = subject
    @recipient = recipient
    mail(to: recipient, :reply_to => email, name: @name, subject: @subject)
  end
end

## user.rb
batch_action :email, form: {subject: :text, message: :textarea}, confirm: "Please enter the subject and the message below", if: proc{ your_condition_here_to_make_this_resource_available } do |ids, inputs|
  batch_action_collection.find(ids).each do |user|
    ContactBatchMailer.contact_batch_email(user.first_name, 'your_address_to_reply_to@example.com', inputs[:message], inputs[:subject], user.email).deliver
  end
  redirect_to collection_path, notice: "The batch email has been sent to all the users you selected."
end
	<!-- Contact batch email -->
	<!DOCTYPE html>
	<html>
	<head>
	<meta content='text/html; charset=UTF-8' http-equiv='Content-Type' />
	</head>
	<body>
	<div>Name: <%= @name %></div>
	<br>
	<div>Subject: <%= @subject %></div>
	<br>
	<div>Reply to: <%= @email %></div>
	<br>
	<div>Message: </div>
	<br>
	<div><p><%= @message %></p></div>
	<br>
	</body>
	</html>
	class ContactBatchMailer < ActionMailer::Base
	default from: "your_address_to_reply_to@example.com"
	def contact_batch_email(name, email, message, subject, recipient)
	@message = message
	@name = name
	@email = email
	@subject = subject
	@recipient = recipient
	mail(to: recipient, :reply_to => email, name: @name, subject: @subject)
	end
	end
	batch_action :email, form: {subject: :text, message: :textarea}, confirm: "Please enter the subject and the message below", if: proc{ your_condition_here_to_make_this_resource_available } do \|ids, inputs\|
	batch_action_collection.find(ids).each do \|user\|
	ContactBatchMailer.contact_batch_email(user.first_name, 'your_address_to_reply_to@example.com', inputs[:message], inputs[:subject], user.email).deliver
	end
	redirect_to collection_path, notice: "The batch email has been sent to all the users you selected."
	end