"Entrys" in the admin

[davidfischer]

This should be pluralized into "entries": https://docs.djangoproject.com/en/1.6/ref/models/options/#verbose-name-plural

[treyhunner]

We probably want to demonstrate that problem in the admin section of the tutorial: https://github.com/pythonsd/test-driven-django-development/blob/master/tutorials/02-models.rst#creating-entries-from-the-admin-site

We'll also need to update the screenshots for that section.

[macro1]

Fixed in #77