Makes the wiki sidebar editable (#5208).

The content of the wiki page named 'Sidebar' is rendered in the sidebar if it exists. Permission to edit protected pages is required to create this page.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@3632 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/wiki.rb

@@ -29,6 +29,12 @@ class Wiki < ActiveRecord::Base
     !user.nil? && user.allowed_to?(:view_wiki_pages, project)
   end
   
+  # Returns the wiki page that acts as the sidebar content
+  # or nil if no such page exists
+  def sidebar
+    @sidebar ||= find_page('Sidebar', :with_redirect => false)
+  end
+  
   # find the page with the given title
   # if page doesn't exist, return a new page
   def find_or_new_page(title)