Set up login in specs for later.

Nearly needed them here but.  Nevermind.
Add SpecialistDocumentRegistry.publish!(document)
Wire up "updated n days ago"
Whitespace.
Add 'publish' button.
DRY up test setup
Clarify test name wording
Use version_number consistently
Merge pull request #3 from alphagov/document-publishing

Document publishing

https://www.pivotaltracker.com/story/show/65351132