refactoring; simplify method_missing in external-parent-chainer
refactoring; simplify method_missing in external-parent-chainer

cyber-dojo/web,byran/cyber-dojo-web,byran/cyber-dojo-web,byran/cyber-dojo-web,cyber-dojo/web,byran/cyber-dojo-web,byran/cyber-dojo-web,byran/cyber-dojo-web,byran/cyber-dojo-web,byran/cyber-dojo-web,cyber-dojo/web,cyber-dojo/web,byran/cyber-dojo-web