Rename and rearrange.

Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Now use our field.

Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Non-null.

Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Show as a text field here.

Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Filter by source.

Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Filter by source, etc.

Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>
Add a get_absolute_url

Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>