Add URLField for linking to uploaded quotes

RIGS/validators.py

@@ -0,0 +1,10 @@
+from urllib.parse import urlparse
+from django.core.exceptions import ValidationError
+
+
+def validate_url(value):
+    if not value:
+        return  # Required error is done the field
+    obj = urlparse(value)
+    if obj.hostname not in ('nottinghamtec.sharepoint.com'):
+        raise ValidationError('URL must point to a location on the TEC Sharepoint')