Included where to put the repo in the instructions

Just in case, like me, the person following the instructions does not
know go all that well. You can make it work without doing things
exactly this way, but you may not get what you expect (because it
might, for example, fetch the weave code from github instead of using
the directory you're in).

README.md

@@ -506,8 +506,16 @@ and the 'run' command like this:
 (NB. This is only necessary if you want to work on weave. Also, these
 instructions have only been tested on Ubuntu.)
 
-To build weave you need `libpcap-dev` and `docker` installed. And
-`go`.
+To build weave you need `libpcap-dev` and `docker` installed. And `go`
+(and `git` and `hg` to fetch dependencies).
+
+The package name is `github.com/zettio/weave`, so assuming `$GOPATH`
+is set:
+
+    $ cd $GOPATH
+    $ mkdir -p src/github.com/zettio
+    $ cd src/github.com/zettio
+    $ git clone https://github.com/zettio/weave
 
 Then simply run