Add sample seed file for internal redirects

The actual redirects will live in alphagov-deployment.

Like 788c978d6281c05ba407d7a58c8bc2b515e1bf63 except that it defaults to
permanent and doesn't need to bypass validation.
File superseded by internal_redirects
Merge pull request #31 from alphagov/internal_redirects_example

Add sample seed file for internal redirects