How to add folder NON RECURSIVELY ?

Hello,

Please consider the following folder structure

` `  `  `
foo/

foo/dir1/file1

foo/dir2/file2
foo/dir2/file3

` ` ` ` ` ` ` 

I like to add the folder structure in a way that only foo/dir1/file1 is added to
the git. foo/dir2 and foo/dir3 should be added to the git also to show the directory
structure and not the contents of those folder.

It is easy in SVN by --non-recursive switch, but how can I do this in git with .gitignore ?

Thanks

BTW: Please CC to me