External task import.

Am trying to figure how to use external tasks. Is the method below the correct way?

tasks.js

```
module.exports = function(rivet) {
require('./hello.js')(rivet);
}
```

hello.js

```
module.exports = function(rivet) {
rivet.desc('say hello');
rivet.task('hello', function() {
console.log('Hello!');
});
}
```

Review the external-task example in tasks.js and hello.js, then inspect the repository's documented task-loading entry points. Determine whether this module pattern is supported and document the correct usage or expected behavior.

Written by the indexing model from the issue text.