Userpreference is missing
ActionView::Template::Error (undefined method `default_users_hide_mail?' for #<Class:0x007fdda8bd8408>):
1: <% include_calendar_headers_tags -%>
2: <% heads_for_wiki_formatter -%>
3: <head>
4: <meta http-equiv="X-UA-Compatible" content="IE=Edge,chrome=1">
5: <meta charset="utf-8" />
app/models/user_preference.rb:29:in `initialize'
app/models/user.rb:856:in `pref'
Happens when installing plugins for Redmine, e.g. Easy Gantt (PRO), Resource managment, Easy WBS, etc. on a old version of Redmine. Just upgrade your Redmine to the current version.
