Patch #mail_to helper to work in Ruby 2.0

See rails/rails#21402 for details.

config/application.rb

@@ -68,6 +68,8 @@ class Application < Rails::Application
 
   require 'publify_login_system'
 
+  require 'active_support_patch'
+
   Date::DATE_FORMATS.merge!(
     :long_weekday => '%a %B %e, %Y %H:%M'
   )

lib/active_support_patch.rb

@@ -0,0 +1,24 @@
+module ActionView
+  module Helpers
+    module UrlHelper
+      # Monkey-patch mail_to to work on Ruby 2.0.
+      # See https://github.com/rails/rails/pull/21402
+      # TODO: Remove once this is part of a Rails release.
+      def mail_to(email_address, name = nil, html_options = {}, &block)
+        html_options, name = name, nil if block_given?
+        html_options = (html_options || {}).stringify_keys
+
+        extras = %w{ cc bcc body subject }.map! { |item|
+          option = html_options.delete(item) || next
+          "#{item}=#{Rack::Utils.escape_path(option)}"
+        }.compact
+        extras = extras.empty? ? '' : '?' + extras.join('&')
+
+        encoded_email_address = ERB::Util.url_encode(email_address.to_str).gsub("%40", "@")
+        html_options["href"] = "mailto:#{encoded_email_address}#{extras}"
+
+        content_tag(:a, name || email_address, html_options, &block)
+      end
+    end
+  end
+end