feat(messages): render markdown in message body

uses redcarpet gem to render markdown to html. Also a html email template
is added.

Gemfile

@@ -128,4 +128,4 @@ group :test do
   gem 'hashie', '~> 3.4.6', require: false # https://github.com/westfieldlabs/apivore/issues/114
 end
 
-gem "redcarpet", "~> 3.6"
+gem "redcarpet"

Gemfile.lock

@@ -653,7 +653,7 @@ DEPENDENCIES
   rails_tokeninput
   ransack
   recurring_select!
-  redcarpet (~> 3.6)
+  redcarpet
   resque
   roo
   roo-xls

app/helpers/application_helper.rb

@@ -263,4 +263,26 @@ module ApplicationHelper
       stylesheet_link_tag foodcoop_css_path, media: 'all'
     end
   end
+
+  # renders html from markdown input
+  def markdown(text)
+    options = {
+        filter_html: true,
+        hard_wrap: true,
+        link_attributes: { rel: 'nofollow', target: "_blank" },
+        fenced_code_blocks: true
+      }
+      extensions = {
+        autolink: true,
+        superscript: true,
+        disable_indented_code_blocks: true,
+        tables: true,
+        strikethrough: true,
+        footnotes: true
+    }
+
+    renderer = ::Redcarpet::Render::HTML.new(options)
+    markdown = ::Redcarpet::Markdown.new(renderer, extensions)
+    markdown.render(text).html_safe
+  end
 end

plugins/messages/app/models/message.rb

@@ -132,11 +132,6 @@ class Message < ApplicationRecord
     user.role_admin?
   end
 
-  def render_markdown
-    markdown = Redcarpet::Markdown.new(Redcarpet::Render::HTML, autolink: true, tables: true, strikethrough: true, footnotes: true)
-    return markdown.render(body)
-  end
-
   private
 
   def create_salt

plugins/messages/app/views/messages/show.haml

@@ -33,7 +33,7 @@
         - if @message.can_toggle_private?(current_user)
           = link_to t('.change_visibility'), toggle_private_message_path(@message), method: :post, class: 'btn btn-mini'
   %hr/
-  = raw @message.render_markdown
+  = markdown(@message.body)
   %hr/
   %p
     = link_to t('.reply'), new_message_path(:message => {:reply_to => @message.id}), class: 'btn'

plugins/messages/app/views/messages/thread.haml

@@ -9,7 +9,7 @@
     .panel-heading
       %b= h(message.sender_name)
       = format_time(message.created_at)
-    .panel-body= simple_format(h(message.body))
+    .panel-body= markdown(message.body)
 
 %p
   = link_to t('.reply'), new_message_path(:message => {:reply_to => thread_message.id}), class: 'btn'

plugins/messages/app/views/messages_mailer/foodsoft_message.html.haml

@@ -1,4 +1,4 @@
-= raw @message.render_markdown
+= markdown(@message.body)
 %hr/
 %pre
   - if @message.group