Create a redirect when editing the title of a page.

app/models/page.rb

@@ -18,20 +18,43 @@ class Page < ActiveRecord::Base
   belongs_to :user, :foreign_key => 'updated_by'
 
   acts_as_versioned :version_column => :lock_version
-  self.non_versioned_columns += ['permalink', 'created_at']
+  self.non_versioned_columns += ['permalink', 'created_at', 'title']
+
+  attr_accessor :old_title # Save title to create redirect page when editing title
 
   validates_presence_of :title, :body
-  validates_uniqueness_of :permalink
+  validates_uniqueness_of :permalink, :title
 
   before_validation_on_create :set_permalink
+  before_validation_on_update :update_permalink
+  after_update :create_redirect
 
   def self.permalink(title)
-    Wikitext::Parser.new.parse "[[#{title}]]"
+    title.gsub(" ", "_")
   end
 
   def set_permalink
-    unless self.permalink.blank?
+    unless title.blank?
       self.permalink = Page.count == 0 ? "Home" : Page.permalink(title)
     end
   end
+
+  protected
+
+  def update_permalink
+    if changed.include?("title")
+      set_permalink
+      self.old_title = changes["title"].first # Save title for creating redirect
+    end
+  end
+
+  def create_redirect
+    unless old_title.blank?
+      Page.create :redirect => id,
+        :title => old_title,
+        :body => "Weiterleitung auf [[#{title}]]..",
+        :permalink => Page.permalink(old_title),
+        :updated_by => updated_by
+    end
+  end
 end