#3: forgot to import ForeignKey

toardb/contacts/models_organisation.py

@@ -3,7 +3,7 @@
 class Organisation (Base)
 =========================
 """
-from sqlalchemy import CheckConstraint, Column, Integer, String, Sequence
+from sqlalchemy import CheckConstraint, Column, Integer, String, Sequence, ForeignKey
 from toardb.base import Base
 
 ORGANISATIONS_ID_SEQ = Sequence('organisations_id_seq')  # define sequence explicitly