fixes a few issues with railsengine.rb

a) Authorization::Engine is already defined in authorization.rb.
Therefore, we must (I believe) rename the Authorization::Engine rail tie.
b) authorization.rb required railsengine.rb which required
lib/declarative_authorization.rb.  This dependency chain made it
impossible to select which pieces from declarative auth you want (if
you're not using ActiveRecord, loading in_model.rb will fail, and
lib/declarative_authorization.rb makes such an attempt).

Signed-off-by: Steffen Bartsch <sbartsch@tzi.org>

lib/declarative_authorization.rb

@@ -9,6 +9,8 @@
   raise "declarative_authorization requires Rails #{min_rails_version}.  You are using #{Rails::VERSION::STRING}."
 end
 
+require File.join(%w{declarative_authorization railsengine}) if defined?(::Rails::Engine)
+
 ActionController::Base.send :include, Authorization::AuthorizationInController
 ActionController::Base.helper Authorization::AuthorizationHelper
 

lib/declarative_authorization/authorization.rb

@@ -1,5 +1,4 @@
 # Authorization
-require File.dirname(__FILE__) + '/railsengine' if defined?(::Rails::Engine)
 require File.dirname(__FILE__) + '/reader.rb'
 require "set"
 

lib/declarative_authorization/railsengine.rb

@@ -1,7 +1,6 @@
-require 'declarative_authorization'
 require 'rails'
 
 module Authorization
-  class Engine < Rails::Engine
+  class RailsEngine < Rails::Engine
   end
 end