Fixes an error that occurs when moving the document by setting another link ID or Scope path. This is due to the fact that author is a required property in the Work model. Patch by: Lennard de Rijk

# Directions for web crawlers.
# See http://www.robotstxt.org/wc/norobots.html.

User-agent: HTTrack
User-agent: puf
User-agent: MSIECrawler
User-agent: Nutch
Disallow: /