Add a plugin to handle session persistence. This is based on the

plugin at http://github.com/augustl/session-persistence but modified
to work with rails 2 rather than rails 3.

vendor/plugins/session-persistence/lib/session_persistence.rb

@@ -0,0 +1,30 @@
+module SessionPersistence
+  private
+  
+  # Override this method if you don't want to use session[:_remember_for].
+  def session_persistence_key
+    :_remember_for
+  end
+
+  # Persist the session.
+  #
+  #   session_expires_after 1.hour
+  #   session_expires_after 2.weeks
+  def session_expires_after(seconds)
+    session[session_persistence_key] = seconds 
+  end
+  
+  # Expire the session.
+  def session_expires_automatically
+    session.delete(session_persistence_key)
+  end
+  alias_method :expire_session, :session_expires_automatically
+  
+  def _persist_session
+    if session[session_persistence_key]
+      request.session_options = request.session_options.dup
+      request.session_options[:expire_after] = session[session_persistence_key]
+      request.session_options.freeze
+    end
+  end
+end