goadesign/examples: cellar/storage.go; 22 LoC

Found a possible issue in [goadesign/examples](https://www.github.com/goadesign/examples) at [cellar/storage.go](https://github.com/goadesign/examples/blob/175371c1d354dca843ba22caa05d77fee5690e3c/cellar/storage.go#L87-L108)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first issue it finds, so please do not limit your consideration to the contents of the below message.

> reference to rating was used in a composite literal at line 102

[Click here to see the code in its original context.](https://github.com/goadesign/examples/blob/175371c1d354dca843ba22caa05d77fee5690e3c/cellar/storage.go#L87-L108)

Click here to show the 22 line(s) of Go which triggered the analyzer.

```go
for rating, ids := range p {
for _, id := range ids {
var b storage.StoredBottle
if err = s.db.Load("CELLAR", id, &b); err != nil {
if err == ErrNotFound {
continue
}
}
sb := storage.StoredBottle{
ID: id,
Name: b.Name,
Winery: b.Winery,
Vintage: b.Vintage,
Composition: b.Composition,
Description: b.Description,
Rating: &rating,
}
if err = s.db.Save("CELLAR", id, &sb); err != nil {
return err // internal error
}
}
}

```

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commit ID: 175371c1d354dca843ba22caa05d77fee5690e3c