Merge pull request #449 in RMS/api-main-service from gladys-dev2 to RMSv2

* commit 'f06a076e':
  cascade

app/entities/models.py

@@ -454,7 +454,7 @@ class BaseApprover(models.Model):
         Delegation,
         blank=True,
         null=True,
-        on_delete=models.DO_NOTHING,
+        on_delete=models.CASCADE,
         to_field='code')
     created = models.DateTimeField(
         blank=True,