Fixes related to the rails 4.1 upgrade

Squashed commit of the following:

commit 98c0043da36df291e461e416b12653a3b232527a
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu May 15 09:36:49 2014 +0200

    Remove issue.mkd; update seeds

commit 35372200028a809270f2634561b968ca65f92fa9
Author: Thomas Schank <DrTom@schank.ch>
Date:   Sun May 11 21:44:27 2014 +0200

    Fix resilient attachment

commit 264d5be468c4502a5a4373964adfbf9fe01a8e48
Author: Thomas Schank <DrTom@schank.ch>
Date:   Sun May 11 20:01:33 2014 +0200

    Fix broken queries (caused by keeping default scopes as of Rails 4.1)
Revamp welcome/about page; show version on it