As I'm following through the doc from a fresh checkout, I get errors at this point running the tests due to missing dependencies (or deps at the wrong version). We should include a section before this one, instructing the user to:
```
$ go get -d github.com/juju/juju/...  # download all the deps, but don't compile yet (because versions aren't set)
$ go get launchpad.net/godeps  # install godeps if you don't already have it
$ godeps -u dependencies.tsv  # assuming cwd: $GOPATH/src/github.com/juju/juju
```

We should set the new developer up to have a working build before running tests as they're stepping through this doc.