Before adding it to the documentation, I did test this and unfortunately, it does not compile. might be a type problem I do not understand yet. I put the following in my example:

```scala
mappings in Universal <++= (packageBin in Compile, target) map { (_, target) =>
  directory(target / "streams")
}
```

And loading the project, I have obtained the following error: 
```
> reload
[info] Loading project definition from /Users/ivan/****
/Users/ivan/****/build.sbt:49: error: value / is not a member of java.io.File
  directory(target / "streams")
                   ^
[error] Type error in expression
```
Do you have any idea about this problem ?