Add ability to configure Reply-To address in gitlab.yml

Closes #1305

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 
 v 7.10.0 (unreleased)
+  - Add ability to configure Reply-To address in gitlab.yml (Stan Hu)
   - Fix broken side-by-side diff view on merge request page (Stan Hu)
   - Set Application controller default URL options to ensure all url_for calls are consistent (Stan Hu)
   - Allow HTML tags in Markdown input

app/mailers/notify.rb

@@ -19,7 +19,7 @@ class Notify < ActionMailer::Base
   default_url_options[:script_name] = Gitlab.config.gitlab.relative_url_root
 
   default from: Proc.new { default_sender_address.format }
-  default reply_to: "noreply@#{Gitlab.config.gitlab.host}"
+  default reply_to: Gitlab.config.gitlab.email_reply_to
 
   # Just send email with 2 seconds delay
   def self.delay

config/gitlab.yml.example

@@ -49,6 +49,7 @@ production: &base
     # Email address used in the "From" field in mails sent by GitLab
     email_from: example@example.com
     email_display_name: GitLab
+    email_reply_to: noreply@example.com
 
     # Email server smtp settings are in config/initializers/smtp_settings.rb.sample
 

config/initializers/1_settings.rb

@@ -103,6 +103,7 @@ Settings.gitlab['protocol']   ||= Settings.gitlab.https ? "https" : "http"
 Settings.gitlab['email_enabled'] ||= true if Settings.gitlab['email_enabled'].nil?
 Settings.gitlab['email_from'] ||= "gitlab@#{Settings.gitlab.host}"
 Settings.gitlab['email_display_name'] ||= "GitLab"
+Settings.gitlab['email_reply_to'] ||= "noreply@#{Settings.gitlab.host}"
 Settings.gitlab['url']        ||= Settings.send(:build_gitlab_url)
 Settings.gitlab['user']       ||= 'git'
 Settings.gitlab['user_home']  ||= begin

spec/mailers/notify_spec.rb

@@ -7,9 +7,12 @@ describe Notify do
 
   let(:gitlab_sender_display_name) { Gitlab.config.gitlab.email_display_name }
   let(:gitlab_sender) { Gitlab.config.gitlab.email_from }
+  let(:gitlab_sender_reply_to) { Gitlab.config.gitlab.email_reply_to }
   let(:recipient) { create(:user, email: 'recipient@example.com') }
   let(:project) { create(:project) }
 
+  around(:each) { ActionMailer::Base.deliveries.clear }
+
   before(:each) do
     email = recipient.emails.create(email: "notifications@example.com")
     recipient.update_attribute(:notification_email, email.email)
@@ -27,6 +30,11 @@ describe Notify do
       expect(sender.display_name).to eq(gitlab_sender_display_name)
       expect(sender.address).to eq(gitlab_sender)
     end
+
+    it 'has a Reply-To address' do
+      reply_to = subject.header[:reply_to].addresses
+      expect(reply_to).to eq([gitlab_sender_reply_to])
+    end
   end
 
   shared_examples 'an email starting a new thread' do |message_id_prefix|