Error where new thread could not be created because the check of old was wrong.

brewman/brewman/views/messaging.py

@@ -26,7 +26,7 @@ def save(request):
     user_id = uuid.UUID(authenticated_userid(request))
     user_name = User.by_id(user_id).name
     title = request.json_body['Title'].strip()
-    if Thread.by_title(title) is None:
+    if Thread.by_title(title) is not None:
         raise ValidationError('Message with same title already exists')
     thread = Thread(title=title, priority=request.json_body['Priority'], user_id=user_id)
     DBSession.add(thread)