Intervention relations enhancements

* refactors model relation to compensation and payment by applying 1-n instead of n-n

compensation/models.py

@@ -12,6 +12,7 @@ from django.utils import timezone
 from django.utils.timezone import now
 
 from compensation.settings import COMPENSATION_IDENTIFIER_LENGTH, COMPENSATION_IDENTIFIER_TEMPLATE
+from intervention.models import Intervention
 from konova.models import BaseObject, BaseResource, Geometry
 from konova.utils.generators import generate_random_string
 from organisation.models import Organisation
@@ -29,6 +30,13 @@ class Payment(BaseResource):
         blank=True,
         help_text="Refers to german money transfer 'Verwendungszweck'",
     )
+    intervention = models.ForeignKey(
+        Intervention,
+        null=True,
+        blank=True,
+        on_delete=models.CASCADE,
+        related_name='payments'
+    )
 
 
 class CompensationControl(BaseResource):
@@ -81,6 +89,14 @@ class Compensation(BaseObject):
     geometry = models.ForeignKey(Geometry, null=True, blank=True, on_delete=models.SET_NULL)
     documents = models.ManyToManyField("konova.Document", blank=True)
 
+    intervention = models.ForeignKey(
+        Intervention,
+        on_delete=models.CASCADE,
+        null=True,
+        blank=True,
+        related_name='compensations'
+    )
+
     # Users having access on this object
     users = models.ManyToManyField(User)