Ability to assign issues to groups (#2964).

Option is disabled by default. It can be turned on in application settings.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@6306 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/views/issue_categories/_form.rhtml

@@ -2,5 +2,5 @@
 
 <div class="box">
 <p><%= f.text_field :name, :size => 30, :required => true %></p>
-<p><%= f.select :assigned_to_id, @project.users.sort.collect{|u| [u.name, u.id]}, :include_blank => true %></p>
+<p><%= f.select :assigned_to_id, @project.assignable_users.sort.collect{|u| [u.name, u.id]}, :include_blank => true %></p>
 </div>