Push.setMetadata working?

Hi I'm trying to attach some metadata to my tokens but not sure if it's my fault or a bug
I want to filter messages by channels and channels could be changed by the app user
In my code

```
Meteor.startup(function () {
Push.addListener('message', function(notification) {
// Called on every message
console.log(JSON.stringify(notification));
});
Push.setMetadata({channels: ['all', 'news', 'events', 'alerts', 'advises']});
});
```

log

```
20151219-23:04:22.930(1)? Push: Got push token from app: { id: 'xRb8wSmbbfRmtChCT',
I20151219-23:04:22.931(1)? token: { gcm: 'xxx' },
I20151219-23:04:22.931(1)? appName: 'main',
I20151219-23:04:22.931(1)? userId: null,
I20151219-23:04:22.931(1)? metadata: { channels: [ 'all', 'news', 'events', 'alerts', 'advises' ] } }
I20151219-23:04:22.936(1)? Push: updated { _id: 'xRb8wSmbbfRmtChCT',
I20151219-23:04:22.936(1)? token: { gcm: 'xxx },
I20151219-23:04:22.936(1)? appName: 'main',
I20151219-23:04:22.936(1)? userId: null,
I20151219-23:04:22.936(1)? enabled: true,
I20151219-23:04:22.936(1)? createdAt: Sat Dec 19 2015 22:38:26 GMT+0100 (CET),
I20151219-23:04:22.937(1)? updatedAt: Sat Dec 19 2015 22:58:50 GMT+0100 (CET) }
```

In mongo

```
{
"_id" : "sRb8wSmbafRmtChCT",
"token" : {
"gcm" : "xxx"
},
"appName" : "main",
"userId" : null,
"enabled" : true,
"createdAt" : ISODate("2015-12-19T21:38:26.423Z"),
"updatedAt" : ISODate("2015-12-19T22:04:22.932Z")
}
```

Start at the Push.setMetadata call and trace how the token record is updated after the metadata appears in the log. Compare that update with the Mongo document shown; done means the metadata is persisted on the token record and remains usable for channel filtering.

Written by the indexing model from the issue text.