Show private messages in foodsofts index pages (fixes #106)

plugins/messages/app/views/message_threads/_groupmessage_threads.html.haml

@@ -1,4 +1,4 @@
-- message_threads = Message.pub.threads.where(group: group).order(created_at: :desc).limit(5)
+- message_threads = Message.readable_for(current_user).threads.where(group: group).order(created_at: :desc).limit(5)
 - unless message_threads.empty?
   %section
     %h3

plugins/messages/app/views/message_threads/_message_threads.html.haml

@@ -1,5 +1,5 @@
 - if pagination
-  - if Message.pub.count > 20
+  - if Message.readable_for(current_user).count > 20
     = items_per_page
   = pagination_links_remote message_threads