Spec template to scaffold controller with factory girl and should matche...

...rs

I like to use the `rails g scaffold` to give a heads up in CRUD things, but the default provided for rspec-rails isn't so good for us, because it doesn't use the factory girl and shoulda matchers. So we end up creating manually. 

The added file will override the default provided for rspec-rails to generate the [following output](https://gist.github.com/marcioj/887da3d9fce9efe5dc6f), which is more close to what we do. The generated test bring 100% of test coverage, but don't create a mess up file.

Any sugestion in become this generated test better is welcome.