"pattern:" does not work in CLI

Somehow i can only add files to my collection by setting the metadata collection in the file.
I can not select any files with the pattern attribute like following:

``` json
"metalsmith-collections": {
"articles": {
"pattern": "*.md"
}
}
```

or

``` json
"metalsmith-collections": {
"articles": "*.md"
}
```

This will only give me an empty collection in the template

No source file or test is named in the issue. Start by reproducing the CLI configuration with both pattern forms and inspect how the collection metadata is parsed; done means matching .md files appear in the articles collection instead of an empty collection.

Written by the indexing model from the issue text.