Merge @dadosch's changes & fix dependency conflicts

src/documents/models.py

@@ -10,7 +10,10 @@ from collections import OrderedDict
 from fuzzywuzzy import fuzz
 
 from django.conf import settings
-from django.core.urlresolvers import reverse
+try:
+    from django.core.urlresolvers import reverse
+except ImportError:
+    from django.urls import reverse
 from django.db import models
 from django.template.defaultfilters import slugify
 from django.utils import timezone