如何使用gogo / protobuf获取自定义go类型

My code in .proto file currently looks like this:

message Category {
    int64 CategoryID = 1;
}

message Categories {
    repeated Category cat = 1;
}

When I run protoc --gogofaster_out=. *.proto the output I get is:

type Category struct {
    CategoryID int64
}

type Categories struct {
    Cat []*Category
}

But what I actually want is:

type Category struct {
    CategoryID int64
}

type Categories []*Category

What does my code in .proto file need to be to get the desired output?