Performing update of Database from version 6 to version 7
  Updating DB from version 6 to version 7
   [6 => 7]  Opening old version DB: /home/qq/Dev/GLBackend/workingdir/db/glbackend-6.db
   [6 => 7]  default Node migration assistant
   [6 => 7]  User migration assistant: #4
   [6 => 7]  default Context migration assistant: #2
   [6 => 7]  default ReceiverTip migration assistant: #1
   [6 => 7]  default WhistleblowerTip migration assistant: #1
   [6 => 7]  default Comments migration assistant: #0
   [6 => 7]  default InternalTips migration assistant: #1
   [6 => 7]  default Receivers migration assistant: #3
   [6 => 7]  default ReceiverContext migration of reference tables: #4
   [6 => 7]  default InternalFile migration assistant: #1
   [6 => 7]  default ReceiverFile migration assistant: #1
Failure in migrate_ReceiverFile: receiverfile.receiver_tip_id may not be NULL 
GlobaLeaks database version 7: update failure :(
Verbose exception traceback: