Routing.root_path() is "" when it should be "/"

In my console:

```
>> include ActionController::UrlWriter
=> Object
>> root_path
=> "/"
```

In the javascript console:

```
>>> Routing.root_path()
""
```

Changing generate.js.erb to:

```
while (path[path.length - 1] == "/" && path != "/") {
```

fixes it.  Does that look right?
