Ignore .DS_Store
Change semantic of ActiveRecord::Base#mutex
Merge branch 'master' of storage.gate.ping.de:/git/active_record_mutex

Conflicts:
	Rakefile
	VERSION
	active_record_mutex.gemspec
	lib/active_record/database_mutex/implementation.rb
	lib/active_record/database_mutex/version.rb
	test/database_mutex_test.rb
	test/test_helper.rb