Added corpse features
Initial migration
Config fabricators.
Add cucumber web step definitions.
Generate Corpse model
Remove duplicate fabricator.
Add cucumber tests

- Given I am on the archive page
- Given I am adding to that corpse
Generate corpses controller
Build corpse controller
Build corpse edit form.
Build corpse new form.
Set routes.
Remove default index.html
Prevent NilClass return when no corpses exist
Append new body and author values on edit.
Add snippet method to Corpse model
Add new_author field to corpse#edit
Add alerts to Archive page.
Add authors field to corpse#new
Update cucumber tests.