cannot load such file -- test_helper (LoadError)

I've installed RubyTest and there is a path problem ...

```
cannot load such file -- test_helper (LoadError)
```

The Problem is the path for test_helper.rb. Generated files have inside:

```
require "test_helper"
```

but this doesn't work at the moment, a temp fix could be to use require_relative like this:

```
require_relative "../test_helper"
```
