add some info about folders to fix #209

Author: quii

hello-world.md

@@ -10,6 +10,8 @@ Make a directory in the following path `$GOPATH/src/github.com/{your-user-id}/he
 
 So if you're on a unix based OS and your username is "bob" and you are happy to stick with Go's conventions about `$GOPATH` (which is the easiest way of setting up) you could run `mkdir -p $GOPATH/src/github.com/bob/hello`.
 
+For subsequent chapters, you can make a new folder with whatever name you like to put the code in e.g `$GOPATH/src/github.com/{your-user-id}/integers` for the next chapter might be sensible. Some readers of this book like to make an enclosing folder for all the work such as "learn-go-with-tests/hello". In short, it's up to you how you structure your folders.
+
 Create a file in this directory called `hello.go` and write this code. To run it type `go run hello.go`.
 
 ```go