v5.3.0

Feature

• Implement copydocumentmutation (613ccd3)
  It is now possible to copy documents
• Split settings file (c80cb4f)
  Useful for integrating caluma as a django app
• Increase max-length of slugs to 150 (5dbfff5)
• Add support for minlength validation (4d67bce)

Fix

• Do not validate row documents when attaching them (fee356a)
• Do not crash when lamenting invalid form slug (42ce73c)
• Handle is_required correctly in nested questions (cb78c08)

Documentation

• Add docs about usage of django apps and interfaces (c164ed3)
• Add hint about snapshot updates and xdist (c026995)